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Home , Glomerulonephrosis, Lupus nephritis

Kidney International, Vol. 7 (1975), p. 254—270

U1rastructure of glomerular disease: A review

JACOB CHURG and EDITH GRISHMAN

Division of RenalPathology, Department of Pathology, Mount Sinai School of Medicine, New York, New York

Electron microscopy was first applied to the study of on the luminal aspect, by the layer of endothelium with the some 25 yr ago. In the early 1950's the nor- numerous perforations, around 100 nm in diameter. It mal ultrastructure was established [1, 21 providing a is likely that these perforations are closed by very basis for the studies of abnormal morphology. A large thin diaphragms [7] which prevent direct contact be- number of papers dealing with human and experi- tween blood and basement membrane. The basement mental renal disease appeared during the next 15 yr membrane consists of three layers: lamina densa, and several comprehensive reviews were published lamina rara externa and lamina rara interna. Lamina in the late 1960's [3—6]. The high resolution of the densa is composed mainly of collagen; it often appears electron microscope enabled the investigators to shed homogeneous, but in good preparations it is found to light on many problems which had caused controversy contain fibrils about 10 nm and also 3 nm in diameter. among the light microscopists, among them the struc- The lamina rara consists mainly of glycoproteins. The ture of the wall in the , the nature lamina rara interna apparently corresponds to, and of the mesangium and its behavior in disease and the possibly represents, the remnant of pericapillary mes- nature and location of "fibrinoid" deposits in various angium, which in certain species (toads, some fishes) glomerular diseases. Electron microscopic studies con- encircles the entire capillary. In man and higher verte- tributed significantly to the understanding of the patho- brates, lamina rara interna may be viewed as a poten- genesis and the morphogenesis of the disease process in tial pericapillary space, which is brought into being by the glomeruli and to a lesser extent in the tubules, the expansion and ingrowth of the mesangium into the interstitial tissue and the blood vessels. Tt also proved to capillary wall or by formation of deposits which may have definite diagnostic value. attain considerable bulk. On the contrary, the epithe- In this review only the more important contributions hal foot processes are firmly anchored to the basement of the earlier periods will be discussed and will be membrane by perpendicular fibers running across supplemented by the more recent information covering lamina rara externa. Subepithelial deposits tend to be approximately the last ten years. small and discontinuous in any plane of section. The foot processes of the are separated by nar- row slits (filtration slits) bridged by a thin layer of Normal ultrastructure cytoplasm (filtration slit membrane) (Fig. 1). The sur- Electron microscopy has clarified the fine details of faces of the epithehial cells, including that of the filtra- structural elements of the glomerulus—capillary wall, tion slit membranes, are covered by a thick coat of mesangium and Bowman's capsule. This is important sialic acid, stainable with collodial iron [8] and ruthe- because all pathological processes in the glomerulus nium red [9]. In addition to the usual cell organelles, can be localized to one or more of these elements and the cytoplasm of the epithelial cells contains many to the spaces defined by them—the capillary lumina microtubules as well as microfibrils. The latter form a and the Bowman's or urinary space. loose network or, in the foot process, dense bundles. As is well known, the capillary wall consists of the The microfibrils resemble myofilaments of smooth basement membrane lined on the urinary aspect by the muscle cells and may possibly endow the cell with epithelial podocytes, which attach to the basement ability to contract [10]. membrane by means of pedicels or foot processes; and Despite much speculation, the specific role of each of the components of the capillary wall and that of the © 1975, by theInternationalSociety of . sialic acid coat in the process of filtration have not been

254 Ultrastructure of glo,nerular disease 255 definitely established. The main filtration barriers are brane causing wrinkling and collapse of [16] probably the basement membrane and the plasma (Fig. 16). membrane of the podocytes, but sialic acid coat may Intracytoplasmic crystals in podocytes have been re- also play a role. ported in some cases of [17, 18] and Electron microscopy has confirmed the existence of cystinosis [19]. the glomerular mesangium and has defined its structure Basement membrane. Thickening of the basement [11]. Normal mesangial cell differs from endothelial membrane occurs in a variety of diseases, among them cell in certain structural aspects; e.g., the presence of mellitus (Fig. 12), systemic erythemato- fine fibrils arranged perpendicularly to the cell mem- sus and . The thickening may reach brane. However, these distinctions often disappear in striking proportions, the membrane attaining ten times disease. More characteristic is the relationship of and more of normal thickness. There may be focal mesangial cells to mesangial matrix which forms a rarefaction (mottling), layering (splitting) or protru- meshwork separating the cells from each other and sions on the endothelial aspect. The latter are common from endothelial cells. This relationship persists and is in with minimal glomerular even accentuated in pathologic states. Mesangial disease. Focal splitting may be seen in a variety of matrix is similar in composition to that of basement diseases, but extensive splitting into multiple layers is membrane, but is not identical; witness its response to characteristic of certain forms of hereditary certain toxins such as Habu snake poison which dis- [20] (Fig. 19). Occasionally, basement membranes solves mesangial matrix but does not affect basement show gaps or breaks which are particularly frequent in membrane [12]. rapidly progressive (extracapillary) glomerulonephritis (Fig. 4). Segments of broken membrane may be phago- cytosed by adjacent cells of a crescent [21]. Gaps may General pathology of the glomerulus also be observed in association with necrosis or poly- Podocytes. The most conspicuous change of the morphonuclear leukocytic infiltration [22]. podocytes is the loss or fusion of their foot processes, Striking protrusions alternating with electron-dense with replacement by a continuous sheet of cytoplasm deposits on the epithelial surface of the basement [13J (Fig. 15).' This change is apparently due to swell- membrane produce a characteristic picture known as ing of cytoplasm which fills the spaces between foot "membranous transformation" (Fig. 17). This trans- processes [5], and retraction of swollen foot processes formation eventually results in a very thick, nonhomo- as seen by scanning electron microscopy [14]. Despite geneous, irregular and later increasingly uniform the swelling the foot processes retain their dense basement membrane. Such change may occur in certain material; i.e., dense bundles of microfibrils. Loss of forms of idiopathic nephrotic syndrome, in systemic foot processes is usually accompanied by the appear- lupus erythematosus, in subacute and chronic glomer- ance of numerous villi projecting from the free surface ulonephritis and in diabetes mellitus. Severe damage of the cells (Fig. 15). The loss may be limited to a few is repaired by a process akin to scarring, with resultant short stretches or may involve the entire capillary sur- permanent decrease in the capillary permeability. face. It is particularly prominent in the presence of Endothelial cells. A common response to injury is severe and the nephrotic syndrome; abate- diffuse , which causes obliteration of the pores ment of proteinuria coincides with reappearance of and formation of large loose structureless blebs. In foot processes. It is possible that in some instances of acute glomerulonephritis, as well as in toxemia of preg- proteinuria the primary injury occurs in the basement nancy, the edematous cells may completely fill the membrane, in others in the epithelial cells. lumen, interfering with glomerular blood flow and Cell bodies of podocytes respond to disease stimuli filtration. by developing abundant cell organelles [15]. Intracyto- Severe endothelial injury leads to formation of gaps plasmic vesicles and inclusions increase in size and between adjoining cells and separation of the cell from number. Conversely, there may be swelling of the the basement membrane. The latter process occurs in cytoplasm with a diminished number of cell organelles the hemolytic-uremic syndrome [23, 24] (Fig. 18) or ra- indicating hypoactivity. We have observed degenera- diation nephritis [25] (Fig. 11). Crystalline inclusions tion and breakdown of podocytes shortly after the on- in endothelial cells have been seen in a few cases of set of proteinuria. In other instances podocytes may dysproteinemia [26, 27]. become detached from the underlying basement mem- Deposits. Deposits found in the walls of glomerular capillaries and in the mesangium consist of accumula- 1Illustrationsfor this section will be found under Specific tion of poorly soluble organic or inorganic material. Diseases. Most deposits are probably derived from the blood 256 Churg/Grishman stream, either as such or as soluble precursors which over a period of months or years and are eventually in- are precipitated at the site. Deposits visualized by corporated into a greatly thickened basement mem- electron microscopy are classified according to appear- brane. ance, density and location within the capillary wall. "Spherical microparticles" may be found in a variety 1) Subendothelial deposits are found between endo- of diseased glomeruli, usually in subepithelial loca- thelial cells and the basement membrane. Some may tion. They are variously interpreted as results of cellu- actually lie in the subendothelial extension of the mes- lar injury [31] or special forms of protein deposits [321. angium. Most deposits are dense, granular, occasion- Deposits within the basement membrane are prob- ally abundant (systemic lupus erythematosus) (Fig. 8); ably common, but can be recognized only if they suffi- others are particulate (hepatic glomeruloscierosis) or ciently differ in density from the basement membrane fibrillar (Fig. 13) (amyloid, fibrin); still others are itself. They represent extensions of subendothelial or scanty and flocculent (hemolytic-uremic syndrome) subepithelial deposits, but may also be trapped directly (Fig. 18). in the membrane. Some deposits take on an organized structure with A specific type of chronic glomerulonephritis, the layers of light and dark bands resembling "finger- basement membrane "dense deposit disease" [33], is prints" (Fig. 9). They have been found particularly in characterized by the appearance of an abnormally systemic lupus erythematosis, but occur also in other dense substance within the glomerular and tubular diseases and have been produced experimentally by re- basement membranes (Fig. 6). peated immunizations [28] or in host vs. graft syn- Mesangium. The mesangium can become strikingly drome [291. enlarged in disease. In acute , there is Some substances infiltrate the basement membrane exudation of polymorphonuclear leukocytes, edema of and appear on the epithelial side of the capillary (amy- the cytoplasm and proliferation of mesangial cells, bid) (Fig. 13); others elevate the endothelium and followed shortly by laying down of additional mes- form large extraluminal "thrombi" (exudative lesions angial matrix. The expanding mesangium compresses of diabetes mellitus); still others do both (systemic the capillaries; it also invades the capillary wall, sep- lupus erythematosus). Fibrin forms intraluminal arating the endothelium from the basement membrane thrombi and also insinuates between the endothelium and creating a "pericapillary" space (Fig. 5). and the basement membrane. Deposits associated with Resolution of inflammation is accompanied by re- toxemia disappear spontaneously within a few days moval of the exudate as well as of the excess of mes- after delivery. The "wire loops" associated with syste- angial cells and matrix. If resolution is incomplete, the mic lupus erythematosus apparently diminish with proliferated cells eventually give rise to lobular or active treatment. stalk scars and permanently obliterate the glomerular 2) Subepithelial deposits in pure form are consider- capillaries. ably less common than subendothelial deposits. They In certain chronic diseases (e.g., diabetes mellitus, probably consist of smaller molecules, since they are cirrhosis, cyanotic congenital heart disease), there able to cross the basement membrane, but are held is progressive increase in the amount of mesangial back by the epithelial cells. In foreign protein nephritis, matrix, with comparatively little cellular proliferation. the deposits contain / complexes [30]. This process, termed glomeruloscierosis, may also end In acute poststreptococcal glomerulonephritis in man, in glomerular obliteration. there may be striking subepithelial deposits (Fig. 2), Mesangial deposits are similar to those seen in the which appear in the acute stage and are often non- capillary wall and occur under the same circumstances. homogeneous and relatively short-lived. Deposits in Some deposits appear to have special affinity for the membranous nephropathy increase gradually in size mesangial matrix (Fig. 7) and may tend to attain bulky

Fig. 1.Wallof normal glomerular capillary (x 42,500).Arrowsindicate filtration-slit membranes. BM =basementmembrane; En endothelial cell. Fig. 2. Acute proliferative glomerulonephritis (poststreptococcal) (x 2,500). The cellularity is caused by increase in the number of mesan- gial cells and exudations of polymorphonuclear leukocytes. Between the cells there are thin, irregular strands of mesangial matrix. Scattered deposits (humps) can be seen between the basement membrane and the "fused" foot processes. Protein droplets (arrow) are seen in the epithelial cytoplasm. D =deposit;MM =mesangialmatrix. Fig. 3. Rapidly progressive (extracapillary) glomerulonephritis (x 2,500). Cells of the crescent are seen at the top, collapsed capillaries at the bottom. F= fibrin; D =deposit. Fig. 4.Extracapillaryglomerulonephritis (x 3,650). Cells of the crescent on the right, partly collapsed capillaries on the left. Arrows point to breaks in the capillary basement membrane. Ultrastrucfure of gloinerular disease 257 1 'p. a •1l"t • SI S i I p .s.A r' : :7' f1 S 258 Churg/Grishman

dimensions. The mesangium plays also a role in re- (and sometimes consist only of C3); however, bac- moving large molecules or complexes from the circula- terial have not been convincingly demon- tion ([11]. strated in them [39]. In some areas the endothelial lining may be lost and polymorphonuclear leukocytes may be seen in intimate contact with the basement Ultrastructure changes in specific diseases membrane. The usual site of such attachment is an Acute proliferative glomerulonephritis. The classic area opposite the localization of humps [40, 41]. manifestation of acute poststreptococcal or, more With further development of the disease, the podo- generally, postinfectious glomerulonephritis is a hy- cytes become larger with dilatation of endoplasmic percellular, bloodless glomerulus. This hypercellularity reticulum and formation of large vacuoles and inclu- is caused in part by exudation of polymorphonuclear sions [42]; some of the latter represent protein and leukocytes but mainly by proliferation of large mono- lipid droplets. The basement membrane becomes nuclear cells (Fig. 2). The nature of the mononuclear swollen, focally split and mottled. Occasionally, actual cells is still debated. A diminishing number of authors perforations or breaks of the capillary basement mem- consider them to be endothelial. Others straddle the brane occur [40, 22]. At the same time, the electron- question by referring to the cells as "endocapillary", dense subepithelial deposits tend to disappear, even if i.e., enclosed by the capillary (and mesangial) base- the disease persists or progresses. However, in some ment membrane. Suggestion has also been made that cases of persistent disease, the deposits remain or re- the cells represent derived from the blood. appear, and are sometimes accompanied by projec- However, electron microscopy strongly suggests the tions of basement membrane ("spikes"). Resolution of view that the cells are mainly or exclusively of mesan- acute glomerulonephritis is signified by decrease of en- gial origin. While some of the characteristic features dothelial swelling, removal of the proliferated mes- may be lost in the proliferating cells, they remain sur- angial cells and matrix and reopening of the capillaries. rounded by intercellular substance in a manner similar The intensity of glomerular lesions varies. While light to that of normal mesangial cells. The intercellular microscopic features, such as necrosis, or substance resembles normal mesangial matrix and the crescents, have been used for some time to predict the basement membrane, and is presumably laid down by outcome of the disease [43], Hinglais, Garcia-Torres the proliferating cells. Unless wandering macrophages and Kleinknecht [44] were able to correlate ultrastruc- are capable of transformation into mesangial cells, they tural appearance with clinical course. It was found that may be expected to form only collagen. These cells are all patients who recovered had typical "humps" on in close contact with the strands of mesangial matrix, biopsy, while "atypical" humps (i.e., extremely which also become numerous. Expansion of the mes- numerous or contiguous) augured a poorer prognosis. angium leads to the compression of the capillary lumi- Another group of cases showing mild mesangial na. The capillaries are further obstructed by the swell- proliferation, but without humps, recovered fully ing of endothelial cells. Proliferation of the endothelial [44,45J. cells rarely occurs and usually under special circum- Rapidly progressive glomerulonephritis. This is a stances such as thrombosis of capillary lumen. In clinical term which corresponds to the pathologists' severe cases the enlarging mesangium pushes its way "extracapillary glomerulonephritis" with crescent for- into the capillary walls, separating the endothelium mation. Crescents may accompany proliferative gb- from the basement membrane, a process described as merulonephritis (poststreptococcal or other) or occur "mesangial matrix deposition" or "mesangial exten- with little or no proliferation in the tuft. The latter sion" [34] or "circumferential mesangial interposi- type has usually no known etiology and carries poorer tion" [35]. The basement membrane is normal at first, prognosis. Crescents are formed through marked pro- though sometimes stretched thin over the expanded liferation of epithelial cells and lead to compression of lobule, or is focally thickened. A characteristic feature the tuft [46] (Fig. 3). Electron microscopy has shown of diffuse proliferative glomerulonephritis is electron- that crescents arise mainly by proliferation of the par i- dense deposits in and around the basement membrane, etal epithelium of Bowman's capsule and to some de- particularly on its epithelial aspect. These deposits are gree of podocytes. The cells of either origin vary in known as "humps". They differ in size, density and appearance and density ("light" and "dark" cells) appearance [32]. Foot processes overlying the deposits (Fig. 3) and exhibit phagocytic and fibroplastic pro- are effaced. The presence of gamma globulin and anal- perties. They produce intercellular substances such as ogy with similar deposits in experimental serum nephri- basement membrane material and collagen fibers, tis [36] suggest antigen-antibody complexes [37, 38]. gradually transforming cellular into fibrous crescents. The deposits also contain C3 component of complement Breaks in the glomerular capillary walls are very corn- Ultrastruciure of glomerular disease 259 mon (Fig. 4) and contribute to the leakage of fibrin An interesting observation is the frequent occur- and red blood cells (Fig. 3). Subepithelial deposits are rence of mesangio-capillary glomerubonephritis in as a rule absent, though subendothelial and intramem- patients with partial lipodystrophy [51]. The renal in- branous deposits are not infrequent (Fig. 3). In some volvement may be preceded by depression of comple- instances deposits are not recognizable by electron ment level in the serum. microscopy but shows diffuse With progression of disease into the chronic stage, "linear" pattern of IgG and complement along the glomerular permeability and proteinuria tend to de- basement membranes [47]. A similar pattern of de- crease, though on occasion the nephrotic syndrome posits and damage to basement membrane is seen in first develops in advanced chronic glomerulonephritis. experimental Masugi (nephrotoxic serum) nephritis, Uremia of terminal glomerulonephritis is mainly due produced by to basement membrane. to the loss of glomerular circulation, but decreased Morphologically similar to rapidly progressive gb- capillary permeability may be a contributing factor. merulonephritis are the nephritides of Goodpasture's Focal glomerulonephritis. Several types are recog- syndrome, some cases of Schonlein-Henoch disease nized. 1) Focal proliferative glomerulonephritis is and the microscopic form of polyarteritis nodosa. The similar to diffuse proliferative, showing increase in majority of cases of Schonlein-Henoch nephritis, how- mesangial cells and matrix. However, this prolifera- ever, exhibit only focal glomerulitis with thrombosis of tion is limited to only some gbomeruli and to segments capillaries and segmental mesangial and epithelial pro- of these glomeruli. An example is glomerubonephritis liferation. (See Focal glomerulonephritis). in rheumatic . It also occurs in systemic lupus ery- Chronic glomerulonephritis. Chronic glomerulone- thematosus (see following). 2) Focal necrotizing glomer- phritis can be subdivided into early and late stages; ulonephritis may represent a more severe form of the special types, such as lobular and mesangio-capillary preceding. Necrosis is most often due to capillary are recognized. The term "chronic glomerulonephri- thrombosis and probably follows damage or destruc- tis" implies an irreversible, progressive process and is tion of the endothelium. A good example is Schönlein- characterized by increasing mesangial proliferation, Henoch purpura, which involves capillaries of skin and whereby the amount of mesangial matrix gradually many viscera as well as those of gbomeruli. In the latter, outstrips the cellular elements. Capillary collapse, ad- deposits are usually present in the mesangium but hesions to Bowman's capsule and cellular or fibrous mainly under the capillary endothelium. The deposits crescents add to the picture of glomerular disorganiza- have a fluffy, granular and fibrillar appearance [52] and tion. On electron microscopy the mesangial matrix is often contain IgA in addition to IgG, C3 and fibrin. often nonhomogeneous, containing vacuoles, bits of Focal necrotizing gbomerulonephritis is seen in many entrapped cytoplasm as well as lipid and protein (hya- other systemic diseases such as subacute bacterial en- line) deposits, and eventually also fibrils of collagen. docarditis, periarteritis nodosa, Wegener's - This process of glomerular sclerosis involves the mes- tosis, but may also be idiopathic. Necrosis usually angium from the hilus to the lobular centers. leads to segmental crescent formation and may be the Marked centrolobular proliferation produces the precursor of diffuse extracapillary glomerulonephritis. picture of lobular glomerulonephritis, while circum- Nephritis of Goodpasture's syndrome frequently be- ferential proliferation leads to mesangio-capillary gins as a focal process. 3) Focal sclerosing glomerulone- (membranoproliferative) glomerulonephritis (Fig. 5). phritis is defined as a cellular segmental glomerular Both conditions are probably variants of the same en- sclerosis usually accompanied by adhesions to Bow- tity and associated with similar clinical and laboratory man's capsule. It probably represents the final stage features [48]. Both lesions usually show numerous (scars) of necrotizing glomerulonephritis. By definition, electron-dense deposits localized in lobular centers, in this is an inactive process, and should be distinguished a space between basement membrane and endothelium from a somewhat similar but active disease, termed or in the mesangial extensions in the capillary wall [49]. focal (see following). 4) Focal proli- Immunofluorescence microscopy reveals that these de- ferative and sclerosing glomerulonephritis may on occa- posits consist predominantly of complement com- sion be an outcome of incompletely resolved diffuse ponents beginning with C3. A rarer variant of this proliferative glomerulonephritis. There are also pro- condition presents with intramembranous deposits and cesses that are mild but essentially diffuse, though they is therefore called basement membrane-dense deposit may appear on light microscopy as focal and seg- disease (Fig. 6); it was originally described by Berger mental. Their diffuseness is demonstrated by electron and Galle [33] as a separate disease entity. Recent microscopy by the presence of mesangial deposits in all studies suggest, however, that it is an uncommon re- or in the majority of glomeruli. One of these is asso- sponse to injury by a variety of agents [50]. ciated with diffuse mesangial deposition of IgA [53]. 260 Churg/Gris/unai: Ultrastructure of glomerular disease 261

Electron microscopy of such specimens shows promi- occurring in our experience in about 25% of cases of nent mesangial cells and matrix with many dense . Electron-dense deposits, especially deposits in the matrix along the mesangial basement subendothelial, often decrease after immunosuppres- membrane [54] (Fig. 7). Another form of focal, seg- sive treatment, but this does not usually prevent the mental proliferative glomerulonephritis was observed nonspecific mesangial proliferation and scarring [62, by van de Putte, de ia Riviere and van Breda Vriesman in 64]. Electron-dense deposits are also found around a group of 22 patients with . The glomerular tubular basement membranes, capillaries and in the lesion was also associated with mesangial dense de- walls of larger blood vessels. They may occasionally posits which, however, on immunofluorescent micros- show organized "fingerprint-like" structures (Fig. 9) copy contained mainly 1gM, C3 and Clq [55]. which are possibly due to the presence of phospholipids Systemiclupus erythematosus. The nephritis of syste- [65] and have been produced experimentally by re- mic lupus erythematosus is characterized by the pres- peated immunization of mice with egg albumin [28]. ence of numerous electron-dense deposits which Another electron microscopic feature found in al- correspond to the immunoglobulins demonstrated by most all cases of lupus nephritis is membrane-enclosed fluorescence microscopy [56] and presumably repre- tubular arrays within the cytoplasm of endothelial and sent antigen-antibody complexes [57]. The amount and sometimes other cells [66] (Fig. 10). The arrays are, localization of these deposits in the mesangium, sub- however, not specific for lupus. They resemble mor- endo- and subepithelial spaces is probably responsible phologically myxovirus particles, but are composed for the type of lupus nephritis in an individual patient. mainly of phospholipid and acidic glycoprotein [67]. Thus, we can distinguish five forms of lupus nephritis: They are probably not of viral origin having recently minimal, focal, mesangial, diffuse and membranous been produced experimentally in cultured lympho- [58, 59]. In the first two groups, there are usually few cytes, and may be related to the synthesis of gamma (or no) deposits. Mesangial lupus nephritis shows globulins [68]. Hematoxylin bodies which constitute mainly mesangial deposits: the membranous form, the only specific feature of systemic lupus erythemato- subepithelial and mesangial deposits; and diffuse lupus sus have been described in electron microscopic in- nephritis, a mixture of subendothelial (Fig. 8), sub- vestigations [63] but are difficult to recognize epithelial and mesangial deposits. It has been postu- structurally. lated that their localization depends on the molecular Radiation nephritis. Radiation nephritis in man is size of the immune complexes [60]. Mesangial deposits manifested by tubular degeneration and atrophy, in- are the most common, are often present even in asymp- terstitial fibrosis, vascular sclerosis and necrosis and tomatic minimal disease and are probably caused by severe glomerular changes. Rosen et al [69] have the phagocytic activity of the mesangial cells which re- studied one case by electron microscopy. The glomer- move these complexes from the circulation. "Wire uli were hypocellular and contained a large amount of loops" are massive subendothelial deposits of proteins PAS-positive material which restricted the capillary and were originally recognized on light microscopy as lumina. This material was similar to the lamina densa a characteristic feature of lupus nephritis [61]. They of the basement membrane (or the matrix of the mes- are usually found in active diffuse lupus nephritis and angium) and was presumably formed by endothelial connote a poor prognosis [62—64]. Membranous lupus (and mesangial) cells. The glomerular cells were ab- nephritis resembles membranous nephropathy clini- normal, showing vacuoles, distended mitochondria, cally and histologically, but is usually accompanied by lipid droplets and nuclear pleomorphism. Recently, mesangial deposits which are extremely rare in non- the view that arterial structures, including glomeruli, specific membranous nephropathy. While the pure are very sensitive to X-radiation has gained acceptance membranous form of lupus nephritis is quite rare [70]. This idea seems to be supported by experimental (<5%), focal subepithelial deposits are very common, evidence in acute and chronic radiation nephritis of

Fig. 5. Mesangiocapillary (membranoproliferative) glomerulonephritis (x 6,560). The expanded mesangium is seen in the left lower cornerand between the endothelium and the basement membrane. M =mesangium;RBC =redblood cell. Fig. 6. Mesangiocapillary glomerulonephritis (6,560). Prominent "dense deposits" in the basement membrane of capillary walls. Ep = epithelialcell; L =capillarylumen. Fig. 7. 'VgA disease (x 13,600). Deposits in the mesangium, directly under the overlying basement membrane. MC=mcsangial cell; U=urinary space. Fig. 8. Lupus nephritis, diffuse type (x 6,560). Proliferation of mesangium accompanied by "wire-loop" deposits (arrows). 262 Churg/Grish,nan

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Fig.9. Lupus nephritis (><32,300). "Fingerprint" deposit under capillary basement membrane. Fig. 10. Lupus nephritis (x 27,750). "Myxovirus-like particles" in the endothelial cell of a peritubular capillary (center). Fig. 11. Radiation nephritis (rat) (x 11,730). Detachment of endothelium from the capillary basement membrane (arrows). Fig. 12. Diabetic glomerulosclerosis ( x 6,560). Capillary basement membranes are markedly thickened, mesangial matrix is greatly in- creased. Fig. 13. ( x 17,000). Fibrillar amyloid deposits in the capillary wall. Basement membrane is still discernible in places (arrow), thoughheavily infiltrated by amyloid. A =amyloid. rats [25, 71]. Electron microscopic changes consist of However, in diabetes mellitus there is an enhanced degeneration of epithelial cells, detachment of endo- production of carbohydrate—rich subunits which pre- thelial (Fig. 11) as well as glomerular and tubular sumably interfere with packing of the peptide chains epithelial cells with formation of new basement mem- and lead to increased permeability of the membrane branes and mesangiolysis followed by sclerosis. With [72]. Excessive accumulation of mesangial matrix in severe damage the cells disappear and the basement the lobular centers leads to the formation of Kimmel- membranes collapse leading to collapse of glomeruli, stiel-Wilson nodules. Mesangial expansion is further severe tubular atrophy, arterial necrosis and striking augmented by deposits of lipid, protein (y-globulin) shrinkage of the renal parenchyma. and collagen, leading to eventual compression of Diabetes mellitus. The basic glomerular lesions in glomerular capillaries. Exudative (insudative, hyaline) diabetes mellitus are progressive thickening of the lesions of diabetes mellitus consist of protein deposits basement membrane and increase in the amount of the on the inside of the basement membrane, lifting the mesangial matrix (diffuse glomerulosclerosis) (Fig. 12). endothelium and restricting the capillary lumen. Small The abnormal basement membranes and matrix are deposits are also found in Bowman's capsule. Thicken- similar morphologically to their normal counterparts. ing of basement membranes is not limited to the gb- Ulirastructure of glo,nerular disease 263 meruli, but is seen also in the tubules and in capillaries light microscopy are very minimal. On electron micros- elsewhere in the body (retina, skin). Some diabetic copy diffuse thickening of the basement membranes patients with the nephrotic syndrome develop mem- of the glomerular capillaries, of Bowman's capsule and branous nephropathy without other stigmata of dia- of tubules can be seen (Fig. 14). Electron-dense de- betic nephropathy [73, 74]. Osterby and Lundbeck [75] posits may be present in the mesangium. The glomer- described "moon-crater" formations on the epithelial ular and tubular cells often contain multiloculated side of the basement membrane, possibly related to dense bodies which consist of lipid and some admixture basement membrane formation by epithelial cells. of mucopolysaccharides [84]. Similar changes have However, similar "membranous convoluted struc- been observed also in experimental animals [85]. tures" were found by Bariety et al [76] in a great variety Lipoid and focal glomeruloscierosis. The of diseases and interpreted as nonspecific lysis of outstanding electron microscopic feature of lipoid ne- cellular elements. phrosis is disappearance of foot processes of podo- Amyloidosis.Amyloidhas an affinity for connectivecytes, which is due to swelling of cytoplasm and tissue, particularly for the tissue around blood vessels.retraction of interdigitating processes. "Foot process In the glomeruli the amyloid is deposited in the mesan- fusion" is also found in many other diseases, but in gium which expands in a manner analogous to that lipoid nephrosis it is the only morphologic abnormality seen in diabetes mellitus. Amyloid is also deposited in (Fig. 15). It is usually reversible under the influence of the capillary wall, first between the basement mem- therapy. Patients who do not respond to such brane and the endothelium and later within the base- treatment often have focal sclerosing glomerular ment membrane proper and on the epithelial side of lesions which on electron microscopy are characterized the capillary (Fig. 13). Occasionally, amyloid may ap- by collapse of capillaries, expansion of mesangium, pear as spicules on the epithelial side of the basement focal protein dense deposits and swelling of visceral membrane, thus resembling membranous nephropathy epithelium [86]. In some cases, focal glomerulosclero- [77]. Electron microscopy reveals the fibrillar structure sis may be accompnaied by degeneration and detach- of amyloid [78—80]. The fibrils measure 7.5 nm in dia- ment of visceral epithelial cells (Fig. 16). This latter meter and show longitudinal beading of about 10 nm, lesion has been found particularly in young male drug caused by twisting of the component protofibrils. The addicts and is associated with the nephrotic syndrome latter are believed to consist of beta-protein, similar in and rapidly progressing renal failure [16]. composition to the light chain of immunoglobulins [79]. Membranous nephropathy. Membranous nephrop- Another type of fibril may also be present. This mea- athy is characterized in its early stages by small sures about 10 nm in diameter and consists of rings of subepithelial deposits which can sometimes only be alpha-globulin stacked longitudinally [80]. Regardless visualized by electron microscopy or immunofluores- of the type of amyloid, the ultrastructural features re- cence (Fig. 17). Later, the basement membrane (or, main essentially the same. more likely, the ) reacts with the production Hepatic glomeruloscierosis. Many liver diseases are of projections or "spikes" which gradually enlarge accompanied by abnormalities in the kidney. These and encircle the deposits. The latter lose their density consist of progressive thickening of capillary walls and and become incorporated into the markedly thickened expansion of the mesangium. On electron microscopy basement membrane which may reach ten times nor- finely granular deposits may be seen under the endo- mal thickness [87]. In some series, a large number of thelium, in the mesangium and also in the basement diabetics (20%) has been found among patients with membrane. These are sometimes accompanied by small membranous nephropathy though this diabetes is often dense structures up to 100 nm in diameter which have only "chemical" [73]. Membranous nephropathy is a clear center and an irregular periphery. Eventually, believed to be an immune-complex disease, the subepi- mesangial matrix increases in amount and the base- thelial deposits representing the complexes [88]. Only ment membrane becomes thickened leading to progres- in some instances are the antigens known, e.g., in sive obliteration of the glomerulus. The changes are syphilis, malaria, certain tumors or drugs (gold, peni- most prominent in chronic liver diseases (cirrhosis) but cillamine). occur to a lesser degree in acute diseases such as acute Nephritis of the hemolytic-uremic syndrome. The viral hepatitis [81]. hemolytic-uremic syndrome is characterized by acute Similar changes have been produced experimentally hemolytic anemia of a peculiar type with many ab- by ligation of the common bile duct or by administra- normal forms and fragmentation of red blood cells, by tion of carbon tetrachloride [82, 83]. thrombocytopenia, and by acute renal insufficiency. Hypothyroidism. Minor disturbances of renal func- Renal lesions are manifested by obstruction of the gb- tion are encountered in hypothyroidism, but changes by merular capillaries by hyaline thrombi and sometimes 264 Churg/Grishnian

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, .)¶ ___ S Ultrastructure of glomerular disease 265 also of the arterioles: focal cortical necrosis may occur. and preeclampsia are enlarged and bloodless, but not Electron microscopic changes of glomeruli in the acute cellular. The explanation of this change lies in the stage consist of swelling of endothelium and widening striking edema of the endothelial and the mesangial of subendothelial spaces with deposition of loose cells and the consequent obstruction of the capillary granular or fibrillar material and extensions of the lumina. Swelling of the mesangial cells imparts to the cytoplasm of mesangial cells and matrix [23] (Fig. 18). lobular centers a fibrillar or reticulated appearance. Immunofluorescence studies suggest that this material Capillary obstruction is further aggravated by suben- is related to fibrin or fibrinogen. Platelets and red dothelial and mesangial deposits of varying densities blood cell fragments may be found in capillary lumina [95]. Immunofluorescence microscopy has shown a which become severely narrowed. Changes in arterioles large amount of fibrin but little or no immunoglobulins resemble the glomerular findings, with endothelial in these glomeruli [96]. It is therefore probable that the swelling and fibrin deposition within the wall. Renal deposits represent fibrinogen-related material. lesions in thrombotic thrombocytopenic purpura may Transplantation. Electron microscopy has contri- be quite similar, except that this disease is systemic in buted to the analysis of lesions occurring in kidney character. transplants [97,98]. This is particularly true for glomer- Hereditary nephritis. Electron microscopy has helped ular lesions, which on light microscopy may resemble greatly in the understanding of hereditary nephritis. various types of glomerulonephritis. The characteristic finding consists of thickening and In some instances, glomerular lesions of transplants, splitting of glomerular capillary basement membranes particularly isografts, may be due to recurrence of the into multiple thin layers with accumulation of dense original disease or to glomerulonephritis caused by particles between the layers [89—91] (Fig. 19). Several histocompatibility antigens; in the majority of patients, authors [20, 90] have pointed out that there is familiar whose immune responses have been modified by treat- segregation of this lesion, which is found in some ment, glomerular lesions are apparently caused by the families with hereditary nephritis, but not in others. processes of rejection. This suggests that there are several types of familial Such changes are characterized partly by moderate nephritis. mesangial proliferation leading to extension of mesan- Another hereditary nephropathy with basement gial cell processes underneath the endothelium, but membrane changes diagnosable only by electron micros- mainly by alterations in and around the basement copy is the nail-patella syndrome. In this disease membrane [99]. Electron-lucent flocculent subendo- mature collagen fibrils are found in the thickened base- thelial deposits have been described [100, 101] which ment membrane and the mesangial matrix in otherwise can take on extraordinary proportions in long-term normal glomeruli [92] (Fig. 20); this probably con- survivors, leading to marked narrowing of capillary stitutes an aberration of the synthesis of basement lumina [99] (Fig. 22). By immunoferritin technique membrane material. this material has been shown to contain 1gM, IgA and Among the inborn errors of metabolism, cystinosis complement [102, 103]. Fibrin has been demonstrated shows renal changes. In addition to crystals, dark by immunofluorescence microscopy in a linear pattern cells with heavy, fine granulation have been described along the glomerular basement membrane [99] and by in visceral glomerular epithelium, tubules and intersti- electron microscopic visualization (personal observa- tium [93]. In Fabry's disease myelin-like inclusions tion). In some cases electron-dense subepi- or suben- (Fig. 21) composed of phospholipids are found in all dothelial deposits are observed which occasionally can parts of the , usually within lysosomes [94]. be so numerous as to resemble the picture of mem- Toxemia of pregnancy. The glomeruli in eclampsia branous nephropathy in various stages of development

Fig. 14. Hypothyroidism (x 14,800). Mesangium is expanded because of increase in mesangial matrix. The lamina rara of basement membrane is thickened (arrow—upper right). There are many small dense deposits of lipid and also "vacuolated bodies" (arrow—lower left). Fig. 15. Lipoid nephrosis ("minimal" or "nil" disease) (x 5,700). Glomerular capillaries showing diffuse loss of foot processes and many microvilli projecting into the urinary space. Epithelial cells show edema; capillary lumina are filled with "blebs". B =bleb. Fig. 16. Focal glomerular sclerosis (in a drug addict) ( x 9,760). "Basement membrane-like material" (BMLM) and granular and vesicu- lar remnants of cytoplasm filling the spaces between the capillary basement membranes and detached epithelial cells. Fig. 17. Membranous nephropathy—nephrosis of congenital syphilis (x 15,250). Segment of glomerular capillary showing subepithelial deposits separated by narrow "spikes" (arrow). The overlying epithelial foot processes are "fused"; they contain large amount of dense "foot process material ".Notethat nearby foot processes (near the upper edge of the picture) are preserved. FP= foot process. 266 C/zurg/Gris/unan — Ultrastructure of glomerular disease 267

Fig. 18. Hemolytic-uremic syndrome (x 12,750). Part of glomerular capillary wall showing cytoplasm of mesangial cells and strands of mesangial matrix between the endothelium and the basement membrane. Arrow indicates fiocculent material beneath the basement membrane. Fig. 19. Alport syndrome (x 13,600). Capillary wall showing longitudinal splitting of basement membrane and dense particles between the split layers (arrow). Fig. 20. Nail-Patella syndrome (phosphotungstic acid stain, x 8,800). Thickening of glomerular capillary basement membrane and numerous collagen fibers in the basement membrane and in the adjoining mesangium. Fig. 21. Fabry's disease (x 7,300). Myelin-like structures filling the cytoplasm of a glomerular podocyte. (Micrograph courtesy of Dr. B. Panner.)

[104]. Spherical particles [31] of various sizes may be Electron-dense, finely granular deposits have been present subepithelially or within the basement mem- found in medium-sized arteries and between tubular brane [98, 104]. It has been suggested that such parti- basement membranes and interstitial cells [99], cles may represent herpes virus capsids [99], though this is doubted by other authors [104]. Since vascular lesions, especially arterial thickening and narrowing, are common occurrences in trans- Acknowledgments This investigation was supported by Public Health planted kidneys, the glomeruli may show, in addition to rejection phenomena, all the changes of ischemia. Service research grant AM-009 18 from the National The mononuclear cells infiltrating the Institute of Arthritis, Metabolism, and Digestive and tubules have been identified by electron micros- Diseases. cope [97, 100] as large lymphocytes with abundant Reprint requests to Dr. Jacob Churg, Renal Pathology, Mount cytoplasm, rough endoplasmic reticulum, many free Sinai School of Medicine, Fifth Avenue and 100th Street, New ribosomes, but few other cell organelles (Fig. 23). York, New York 10029, U.S.A. - it.. 'C- '.k

Fig. 22. Transplant rejection (x 9,760). Glomerular capillary showing separation of endothelium from basement membrane (left side of picture) with ingrowth of mesangium and deposition of light finely granular material mixed with small dark particles. Fig. 23. Transplant rejection (x 6,560). Part of glomerulus showing collapse of capillaries, widening and wrinkling of basement mein- branes and many cells with abundant rough endoplasmic reticulum in the capillary lumina and in the urinary space. 268 C/iurg/Grishman

References 21. MORITA T, SUZUKI Y, CHURO J: Structure and development of the glomerular crescent. Am JPathoi 72:349—368, 1973 1. PEASE DC, BAKER RF: Electron microscopy of the kidney. 22. STEJSKAL J, PIRANI CL, OKADA M, MANDELANAKIS N, AmJ4nat 87:349—390, 1950 POLLAK VE: Discontinuities (gaps) of the glomerular capil- 2. HALLBY:Studies of the normal glomerular structure by lary wall and basement membrane in renal disease. Lab electron mcroscopy, in Proceedings of the 5rh Annual Con- Invest 28:149—169, 1973 ference on the Nephrotic Syndrome, New York, National 23. VITSKY BH, SUZUKI Y, STRAUSS L, CHURO J: The hemolytic- Nephrosis Foundation, 1953, p. 1. uremic syndrome: A study of renal pathologic alterations. 3. BENCOSME SA, M0RRIN PAF: Ultrastructural pathology of Am JPathol 57:627—647, 1969 the glomerulus, in Ultrastructure of the Kidney, edited by DALTON AF, HAGIJENAIJ F, New York, Academic Press mc, 24. FRANKLIN WA, SIMON NM, POrFER EW, KRUMLOV5KY FA: The hemolytic-uremic syndrome. Arch Pathol 94:230—240, 1967, vol. 2, pp. 143—227 4. CHURG J: Electron microscopic aspects of renal pathology, 1972 in Structural Basis of Renal Disease, edited by BECKER EL, 25. MADRAZO A, SUZUKI Y, CHURG J: Radiation nephritis: New York, Hoeber Medical Division, 1968, pp. 132—196 Acute changes following high dose of radiation. Am J 5. SIMON UT, CIIATELANAT F: Ultrastructure of the normal and Pathol 54:507—527, 1969 pathological glomerulus, in The Kidney, edited by ROUILLER 26. PORUSH JG, G1USHMAN E, ALTER AA, MANDELBAUM H, C, MULLER AF, New York, Academic Press mc, 1969, vol. I, CHURG J: Paraproteinemia and cryoglobulinemia associated pp. 262—349 with atypical glomerulonephritis and the nephrotic syn- 6. CHATELANAT F, SIMON UT: Ultrastructural pathology of the drome. AmJMed47:957—964, 1969 tubules and interstitial tissue, in The Kidney, edited by 27. VERROUST P, MERY JP, MOREL-MAROGER L, CLAUVEL JP, ROUILLER C, MULLER AF, New York, Academic Press mc, RICHET G: Glomerular lesions in monoclonal gammo- 1969, vol. I, pp. 450—530 pathies and mixed essential cryoglobulinemias IgG-IgM. 7. RHODIN JAG: Structure of the kidney, in DIseases of the Adv Nephrol 10:161—194, 1971 Kidney, edited by STRAUSS MB, WELT LU, Boston, Little, 28. OKUMURA K: Induction of a disease resembling systemic Brown and Company, 1971, vol. I, pp. 1—30 lupus erythematosus in C57BL/GJ mice by prolonged im- 8. JONES DB: Mucosubstances of the glomerulus. Lab Invest munization with egg albumin. Acta Pathol Jap 23:695—704, 21:119—125, 1969 1973 9. GRONIOWSKI J, BICZYSKOWA W, WALSKI M: Electron micro- 29. HARD RC, MONAIRE CW, STILL WJS: Renal lesions scope studies on the surface coat of the nephron. J Cell Blot with organized deposits and lipid as part of the host versus 40:585—601, 1969 graft syndrome in parent/F1 mouse chimeras. Lab Invest 28: 10. KARNOVSKY Ml, AINSWORTR SK: The structural basis of 468—476, 1973 glomerular filtration. Adv Nephrol 2:35—60, 1972 30. DIXON FJ, FELDMAN JD, VASQUEZ JJ: Experimental glomer- 11. FARQUHAR MG, PALADE GE: Functional evidence for the ulonephritis: The pathogenesis of a laboratory model re- existence of a third cell type in the renal glomerulus: Phago- sembling the spectrum of human glomerulonephritis. J Exp cytosis of filtration residues by a distinctive "third" cell. Med 113:899—920, 1961 J Cell 8iol 13:55—87, 1962 31. BURKROLDER PM, HYMAN LR, BARBER TA: Extracellular 12. SuzuKi Y, CHURG J, GRISHMAN E, MAUTNER W, DACHS S: clusters of spherical microparticles in glomeruli in human The mesangium of the renal glomerulus. Am J Pathol 43: renal glomerular diseases. Lab Invest 28:415—425, 1973 555-578, 1963 32. CHURG J, GRISEIMAN E: Ultrastructure of immune deposits 13. FARQUHAR MG, VERNIER RL, Goon RA: Application of in renal glomeruli. Ann Intern Med 76: 479—486, 1972 electron microscopy in pathology: Study of 33. BERGER J, GALLE P: Depots denses. au sein des basales du tissues. Schweiz Med Wochenschr 87:501—510, 1957 rein. Presse Med 71:2351—2354, 1963 14. ARAKAWA M: A scanning electron microscope study of the 34. CHURG J, GRISHMAN E, GOLDSTEIN MH, YUNIS SL, PORUSH human glomerulus. Am JPathol 64:457—466, 1971 JG: Idiopathic nephrotic syndrome in adults: A study and 15. TRUMP BF, BENDJTT EP:Electronmicroscopic studies of classification based on renal biopsies. N Engi J Med 272: human renal disease: Observations of normal visceral gb- 165—174, 1965 merular epithelium and its modification in disease. Lab 35. ARAKAWA M, KIMMELSTIEL P: Circumferential mesangial Invest 11:753—781, 1962 interposition. Lab Invest 21:276—284, 1969 16.GRISI-IMANE,CHURGJ:Focalglomerulosclerosis in nephro- 36. DIxON FJ: Renal injury induced by antigen-antibody com- tic patients: An electron, microscopic study of gbomerular plexes and other immunologic means. Fed Proc 24:98—99, podocytes, Kidney mt 7:111—122, 1975 1965 17. R055MAN P, HORNYCH A, ENGLIS M: and ultra- 37. CHURG J, MAUTNER W, GRISHMAN E, EISNER GM: Struc- structure of crystalloid inclusions in the podocytes in a case ture of glomerular capillaries in proteinuria. Arch Intern of paraproteinuria. Virch Arch [Pat/wi Anatl 344:151—158,. Med 109:97—115,1962 1968 38.KIMMELSTIEL P. KIM OJ,, BERES J: Studies on renal biopsy 18. VELOSA JA, MALDONADO JE, HOLLEY KE, WAGONER RD, specimens with the aid of the electron microscope: mm. Gb- KYLE RA, SALASSA RM: Fanconi's syndrome, an expres- merulonephritis and . Am J Clin Pathol sion of evolving myeloma. Abs of the 6th Ann Meet of the 38:280—296, 1962 Am Soc Nephroi, Nov 19—20, 1973, p. 108 39. CHURG J, DUFFY IL: Classification of glomerulonephritis 19. SPEAR G: The proximal tubule and the podocyte in cystino- based on morphology, in Glomerulonephritis—Morphology, sis. Nephron 10:57—60, 1973 Natural History, and Treatment, edited by KINCAID-SMITH P, 20. CHURG J. SHERMAN RL:. Pathologic characteristics of here- MATIIEW TH, BECKER EL, New York, John Wiley & Sons, ditary nephritis. Arch Pathol 95:374—379, 1973 1972, part 1, pp. 43—61 Ultrastructure of glotnerular disease 269

40. BURKHOLDER PM: Ultrastructural demonstration of injury genic specificity and relation to disease. J Exp Med 134:294— and perforation of glomerular capillary basement membrane 312, 1971 in acute proliferative glomerulonephritis. Am J Pathol 56: 58. MCCLUSKEY RT: Lupus nephritis, in Pathology Annual, 251—265, 1969 edited by SOMMERS SC, New York, Appleton-Century. 41. M0RITA T, WENZL JE, KIMMELSTIEL P: The relationship of Crofts, 1970, pp. 125—144 neutrophilic and eosinophilic leukocytes to the glomerular 59. KOFFLER D, AGNELLO V, CARR RI, KLJNKEL HG: Variable capillary basement membrane in acute proliferative glomer- patterns of immunoglobulin and complement deposition in ulonephritis. Lab Invest 25: 445—450, 1971 the kidneys of patients with systemic lupus erythematosus. 42. STRUNK SW, HAMMOND WS, BENDITT EP: The resolution of Am JPathol 56:305—316, 1969 acute glomerulonephritis: An electron microscopic study of 60. GERMUTH FG, RODRIGUEZ E: Deposit and four sequential biopsies. Lab Invest 13:401—429, 1964 Antibasement Membrane Disease. Boston, Little, Brown and 43. HEPTINSTALL RH: Pathologyofthe Kidney. Boston, Little, Company, 1973 Brown and Company, 1966 61. KLEMPERER P, POLLACK AD, BAEHR G: Pathology of dis- 44. HINGLAIS N, GARCIA-TORRES R, KLEINKNECHT C Long- seminated lupus erythematosus. Arch Pathol 32:569—631, term prognosis in acute glomerulonephritis: The predictive 1941 value of early clinical and pathologic features observed in 62. DUJOVNE I, P0LLAK yE, PIRANI CL, DILLARD MG: The dis- 65 patients. Am J Med 56:52—60, 1974 tribution and character of glomerular deposits in systemic 45. Prognosis and pathology in acute glomerulonephritis lupus erythematosus. Kidney Int 2:33—50, 1972 (editorial). Lancet 1:787—792, 1974 63. COMERFORD FR, COHEN AS: The nephropathy of systemic 46. BACANI RA, VELASQUEZ F, KANTER A, PIRANI CL, POLLAK lupus erythematosus: An assessment of clinical, light, and VE: Rapidly progressive (non-streptococcal) glomerulone- electron microscopic criteria. Medicine 46:425—473, 1967 phritis. Ann Intern Med 69:423—485, 1968 64. GRISHMAN E, PORUSH JG, LEE SL, CHURG J: Renal biopsies 47. LEWIS EJ, CAVELLO T, HARRINGTON JT, COTRAN RS: An in lupus nephritis: Correlation of electron microscopic immunopathologic study of rapidly progressive glomerulo- findings with clinical course. Nephron 10:25—36, 1973 nephritis in the adult. Human Pathol 2:185—208, 1971 65. WOOD C: Crystalline phospholipid deposits in renal glomer- 48. HABIB R, KLEINKNECHT C, GUBLER MC, LEVY M: Idio- uli in glomerulonephritis (abstract). Am J Pathol 66: 59a pathic membranoproliferative glomerulonephritis in child- 1972 ren: Report of 105 cases. C/in Nephrol 1: 194—214, 1973 66. GYORKEY F, SINKOVICS J, MIN KW, GYORKEY P: A morpho- 49. CAMERON JS, OGG CS, TURNER DR, WELLER RO, WHITE logic study on the occurrence and distribution of structures RHR, GLASCOW EF, PETERS DK, MARTIN A: Mesangio- resembling viral nucleocapsids in collagen diseases. Am J capillary glomerulonephritis and persistent hypocomple- Med53:148—158, 1972 mentemia, in Glomerulonephritis—Morphology, Natural 67. SCHAFF Z, BARRY DW, GRIMLEY PM: Cytochemistry of History, and Treatment, edited by KINCAID-SMITFI P, tubuloreticular Structures in lymphocytes from patients with MATHEW TH, BECKER EL, New York, John Wiley & Sons, systemic lupus erythematosus and in cultured human lym- 1972, part I, pp. 541—556 phoid cells: Comparison to a paramyxovirus. Lab Invest 29: 50. JENI5 EH, SANDLER P, HILL GS, KNEISER MR, JENSEN GE, 577—586, 1973 ROSKES SD: Glomerulonephritis with basement membrane 68. POTHIER L, UZMAN BG, KASAC MM, SAITO H, ADAMS RA: dense deposits. Arch Pathol 97:84—91, 1974 Immunoglobulin synthesis and tubular arrays in the endo- 51. PETERS DK, WILLIAMS DG, CHARLESWORTH JA, B0uLT0N- plasmic reticulum in transplanted human tumors of lym- JONES JM, SissoNs JGP, EVANS DJ, KOURILSKY 0, MOREL- phoid origin. Lab Invest 29:607—613, 1973 MAROGER L: Mesangiocapillary nephritis, partial lipody- 69. ROSEN S. SWERDLOW MA, MUEHRCKE RC, PIRANI CL: strophy, and hypocomplementaemia. Lancet 2:535—538, Radiation nephritis: Light and electron microscopic ob- 1973 servations. Am J C/in Pathol 41:487—502, 1964 52. URIZAR RE, MICHAEL A, SISS0N S, VERNIER RL: Anaphy- 70. LUXTON RW: Effects of irradiation on the kidney, in lactoid purpura: II. Immunofluorescent and electron micro- Diseases of the Kidney, edited by STRAUSS MB, WELT LG, scopic studies of the glomerular lesions. Lab Invest 19:437— Boston, Little, Brown and Company, 1971, vol.11, pp. 1049— 450, 1968 1070 53. BERGER J: IgA glomerular deposits in renal disease. Trans- 71. MADRAZO A, SUZUKI Y, CIIURG J: Radiation nephritis: II. plant Proc 1:939—944, 1969 Chronic changes after high doses of radiation. Am J Pathol 54. DAVIES DR, TIGHE JR, JONES NF, BROWN GW: Recurrent 61:37—56, 1970 hematuria and mesangial IgA deposition. J Cliii Pathol 26: 72. SPIRO RG: Biochemistry of the renal glomerular basement 672—677, 1973 membrane and its alterations in diabetes mellitus. N Engl J 55. VAN DE PUTTE LBA, DE LA RIVIERE GB, VAN BREDA Med288: 1337—1342, 1973 VRIESMAN PJC: Recurrent or persistent hematuria: Sign of 73. EHRENREICH T, GRISHMAN E, CHURG J: Glucose dysmeta- mesangial immune-complex deposition. N Engi J Med 290: bolism and membranous nephropathy (abstract). Am J 1165—1170, 1974 Pathol 74:33A, 1974 56. MELLORS RC, ORTEGA LG, HOLMAN HR: Role of gamma 74. WARMS PC, ROSENBAUM BJ, MICHELIS MF, HAAS JE: Idio- globulins in pathogenesis of renal lesions in systemic lupus pathic membranous glomerulonephritis occurring with dia- erythematosus and chronic membranous glomerulone- betes mellitus. Arch Intern Med 132:735—738, 1973 phritis, with an observation on lupus cell reaction. J Exp 75. OSTERBY R, LUNDBAEK K: The basement membrane mor- Med 106:191—202, 1957 phology in diabetes mellitus, in Diabetes Mellitus, edited by 57. KOFFLER D, CARR R, AGNELLO V, THOBURN R, KUNKEL ELLENBERG M, RIFKIN H, New York, McGraw-Hill Book HG; Antibodies to polynucleotides in human sera: Anti- Co mc, 1970, pp. 178—209 270 Churg/Grishman

76. BARIETY J, CALLARD P, APPAY MD, GROSSETETE J, MANDET 92. MORITA T, LAUGHLIN LO, KAWANO K, KIMMEL5TIEL P, C: Ultrastructural study of some frequent and poorly known SUZUKI Y, CHURG J: Nail-patella syndrome: Light and intraglomerular structures. Adv Nephro/ 3: 153—172, 1974 electron microscopic studies of the kidney. Arch Intern Med 77. ANSELL ID, JoEKasAM:Spicular arrangement of amyloid in 131:271—277, 1973 renalbiopsy. JC/in Pathol 25:1056—1062, 1972 93. SPEAR OS, SLU55ER RI, T0U5IMI5 Al, TAYLOR CU: Cystino- 78. COHEN AS: Amyloidosis: Preliminary chemical analysis of sis: An ultrastructural and electron-probe study of the partially purified amyloid fibrils. LabInvest 15:64—83,1966 kidney with unusual findings. Arch Pathol 21:206—221, 1971 79. OLENNER GO,TERRYW, HARADA M, IsaRsicY C, PAGE D: 94.MALMQvIsT E, IVEMARK BI, LIND5TEN J, MAUN5BACH AB, Amyloid fibril proteins: Proof of homology with immuno- MARTENSSON E: Pathologic lysosomes and increased urinary globulin light chains by sequence analysis. Science172: glycosylceramide excretion in Fabry's disease: Studies on a 1150—1151,1971 family with evidence of linkage with the sex-linked blood 80.HIR5CHL 5: Electron microscopic analysis of human amy- group Xg. Lab Invest 25: 1—14, 1971 bid. JUltrastruct Res 29:281—292,1969 95.MAUTNERW,CHURG J, GRI5HMAN E,DACH55: Preeclamp- 81. SAKAGUCHI H, DAcH5 5, GRISHMAN F, PARoNano F, tic nephropathy: An electron microscopic study. Lab Invest SAL0M0NM,CHURGJ: Hepatic gbomerulosclerosis: An 11:518—530,1962 electron microscopic study of renal biopsies in liver diseases. 96. SIMsEAH:The kidney in pregnancy, in Diseasesof the LabInvest 14:533—545, 1965 Kidney(2nd ed), edited by STRAuss MB, WELT LG, Boston, 82.SAKAGUCHI H, GRI5HMAN E, CHURG J: Renal glomerulus in Little, Brown and Company, 1971, pp. 1155—1205 obstructive jaundice. ArchPaihol 79:512—517, 1965 97. RO5ENAUW,LEE JC, NAJARIANJS:Alight, fluorescence,and 83. SAKAGUCHI H, DACH5 5, MAUTNER W, GRISHMAN E, electronmicroscopic study of functioning humanrenal trans- CHURG J: Renal glomerular lesions after administration of plants. Surg Gyn Obst 128:62—76, 1969 carbon tetrachloridc and ethionine. Lab invest 13:1418— 98. RowLANos DT, BURKHOLDERPM,BossaN EH, LINHH: 1426, 1964 Renal allografts in HL-A matched recipients. Am J Pathol 84.DISCALA VA, SALOMON M, GRISHMAN E, CHURG J: Renal 61:177—210,1970 structure in myxedema. Arch Patho/ 84: 474—485, 1967 99. BUSCH GJ, GALVANEK EU, REYNOLDS ES: Human renal 85. GREEN CR, HAM KN, TANGE JD: Glomcrular lesions in ex- allografts: Analysis of lesionsin long-term survivors. perimental hypothyroidism. Arch Pathol 98:156—160, 1974 HumanPathol 2:253—308, 1971 86. HYMAN LR, BURKHOLDER PM: Focal sclerosing glomerulo- 100. HAMBURGER J,CRO5SIER DORMONTJ, BACH J-F: Renal nephropathy with segmental hyalinosis: A clinicopathologic J, Transplantation. Baltimore,The Williams & Wilkins Co., analysis. Labinvest 28:533—544,1973 1972 87. EHRENREICI-I T, CHURG J: Pathology of membranous ne- 101. OGDEN D: Human renal phropathy, in Pathology Annual, edited by SOMMER5 SC, HULME B, ANDREWG, PORTER K, IV.Gbomerularultrastructure, macromole- New York, Appleton-Century-Crofts, 1968, vol. 3, pp. 145— transplants: 186 cularpermeability, and hemodynamics. Lab Invest 26:2—10, 88. MCCLUSKEY RT: Evidence for immunologic mechanisms in 1972 several forms of human glomerular diseases. Bull N V Acad 102. ANDRE5GA, ACCINNI L,HSU K, PENN I, PORTERK, SEEGAL STARZL T: Human renal transplants: Med46:769—788,1970 RENDALLJ, B, 89. SHERMAN RL, CHURG J, Yums M: Hereditary nephritis with Ill. Immunopathologic studies. Lab Invest22:588—604, 1970 a characteristic renal lesion. Am J Med 56:44—51, 1974 103. PORTER K, ANDRE5 0, CALDER M, DossEToR J, HsuJ, 90. HmGLAis N, GRUNFELD J-P, Bois E: Characteristic ultra- RENDALL K, SEEGALI, STARZLT:Humanrenal transplants: structural lesion of the gbomerular basement membrane in II. Immunofluorescent and immunoferritin studies. Lab progressive hereditary nephritis (Alport's syndrome). Lab Invest 18:159—171, 1968 invest27:473—478,1972 104.OLSEN 5, BOHMAN S-O,POSBORG-PETER5EN V: Ultra- 91. SPEAR G, SLussaR RJ: Alport's syndrome: Emphasizing structureof the glomerular basement membrane in long- electron microscopic studies of the glomerulus. AmJ Pat hal term renal albografts with transplant gbomerular disease. 69:21 3—224, 1972 Lab Invest30:176—189,1974