Hyper IgM immunodeficiency. A primary dysfunction of B lymphocyte isotype switching. D Levitt, … , K Rich, M D Cooper J Clin Invest. 1983;72(5):1650-1657. https://doi.org/10.1172/JCI111124. Research Article Immunological evaluations (lymphocyte markers, B cell differentiation, T cell function) were performed on peripheral blood mononuclear cells from four individuals with hyper IgM immunodeficiency. Number, proportion, and proliferation of T lymphocytes and T lymphocyte subpopulations were relatively normal in affected individuals. The percentage and number of B cells expressing surface IgM and IgD were either normal or elevated in both blood and lymph nodes. However, surface IgG- and IgA-bearing B lymphocytes were completely absent. In vitro stimulation of blood lymphocytes with both T cell-dependent and T-cell independent polyclonal B cell activators resulted in normal numbers of IgM plasma cells and IgM secretion in cultures, but failed to induce any IgG- or IgA-producing cells. This failure of isotype switching was intrinsic to the B cell population and did not involve aberrant T cell help or suppression. Therefore, individuals with this disorder possess an intrinsic B cell dysfunction that is not related to abnormal T cell regulation. Find the latest version: https://jci.me/111124/pdf Hyper IgM Immunodeficiency A PRIMARY DYSFUNCTION OF B LYMPHOCYTE ISOTYPE SWITCHING DANIEL LEVITT, PATRICIA HABER, KENNETH RICH, and MAX D. COOPER, Department of Pediatrics and the La Rabida-University of Chicago Research Institute, University of Chicago, Chicago, Illinois 60649; Departments of Pediatrics and Microbiology, and the Comprehensive Cancer Center, University of Alabama in Birmingham, Birmingham, Alabama 35294; Department of Pediatrics, Children's Memorial Hospital and Northwestern Medical Center, Chicago, Illinois 60611 A B S T R A C T Immunological evaluations (lympho- (1). Initially, the At heavy chain isotype can be detected cyte markers, B cell differentiation, T cell function) without light chains in pre-B cells (2, 3); although pre- were performed on peripheral blood mononuclear cells B cells do not normally switch heavy chain isotypes, from four individuals with hyper IgM immunodefi- some malignant pre-B-like cells appear capable of pro- ciency. Number, proportion, and proliferation of T ducing both y and a chains (4, 5, 6). Cells producing lymphocytes and T lymphocyte subpopulations were each of the heavy chain classes are derived from IgM- relatively normal in affected individuals. The per- bearing B lymphocytes (7). Isotype switching may occur centage and number of B cells expressing surface IgM either during expansion of surface immunoglobulin and IgD were either normal or elevated in both blood (sIg')' B lymphocytes or upon differentiation to plasma and lymph nodes. However, surface IgG- and IgA- cells with subsequent secretion of a single Ig class (8). bearing B lymphocytes were completely absent. In T cells can preferentially enhance or inhibit the dif- vitro stimulation of blood lymphocytes with both T ferentiation of plasma cells to produce certain Ig iso- cell-dependent and T-cell independent polyclonal B types in an antibody response (9-12). cell activators resulted in normal numbers of IgM An immunodeficiency syndrome characterized by plasma cells and IgM secretion in cultures, but failed elevated serum levels of IgM and virtually undetectable to induce any IgG- or IgA-producing cells. This failure quantities of IgG and IgA presents as either an X- of isotype switching was intrinsic to the B cell popu- linked or an acquired disorder (13, 14). Recent evidence lation and did not involve aberrant T cell help or suggests that individuals with this immunodeficiency suppression. Therefore, individuals with this disorder possess normal numbers of IgM-bearing B lymphocytes, possess an intrinsic B cell dysfunction that is not related which can be stimulated by pokeweed mitogen (PWM) to abnormal T cell regulation. to secrete IgM but not IgG (15). Variable abnormalities of T helper and suppressor cell function have also been INTRODUCTION described in blood cells from these patients (16-19). Because PWM normally does not induce substantial IgM is the first antibody class to be expressed during isotype switching by peripheral blood B cells (20-22), B cell development in all of the animal species examined the significance of this finding in terms of heavy chain This study was supported by a Basil O'Connor March of Dimes Research Grant to Dr. Levitt, and National Cancer Institute grant 5-MO1-RR32 and March of Dimes Birth De- ' Abbreviations used in this paper: Bc, control B cell frac- fects Foundation grant 1-608 to Dr. Cooper. Address all cor- tion; Bp, patients' B cell fraction; Con A, concanavalin A; respondence to Dr. Levitt, Guthrie Research Institute, Sayre, EBV, Epstein-Barr virus; PBMC, peripheral blood mono- PA 18840. nuclear cells; PWM, pokeweed mitogen; SA, Staphylococcus Received for publication 20 April 1983 and in revised aureus Cowan I; sIg. surface immunoglobulin; Tc, control form 11 July 1983. T cell fraction; Tp patients' T cell fraction. 1650 J. Cli?l. Invest. () The Amierican Society for Clinical Investigationz, Inic. - 0021-9738/83/11/1650/08 $1.00 lVolunie 72 November 1983 1650-1657 class commitment and expression in hyper IgM im- Patient 4 is a 12-yr-old white male with a family history munodeficiency is unclear. of an uncle who died in infancy after developing agranu- locytosis and Candida sepsis, and whose autopsy revealed We have analyzed the phenotype of peripheral atrophic lymphoid tissue. The patient developed bilateral blood lymphocyte subpopulations from individuals pneumonia at 7 mo of age. No palpable lymph nodes were with hyper IgM immunodeficiency and their function detected and he was significantly neutropenic (Table I). after culture with both T cell-dependent and T cell- Serum immunoglobulins revealed low IgG and IgA, but an elevated IgM. He subsequently developed Pneumocystis independent B cell activators. Our findings indicate carinii pneumonia from which he recovered and is presently that B cells from individuals with this immune disorder in relatively good health. He is treated with intramuscular are unable to switch heavy chain classes, even after gamma globulin every 3 wk. stimulation by several polyclonal activators. The data Isolation of peripheral blood mononuclear cell (PBMC) populations. Heparinized venous blood obtained from nor- also suggest that this defect is independent of T cell mal adult volunteers (ages 18-50 yr) and patients was sep- help or suppression. arated on Ficoll-Hypaque cushions (Pharmacia Fine Chem- icals, Piscataway, NJ). The washed mononuclear leukocyte METHODS (PBMC) were either analyzed for cell phenotype or were depleted of monocytes (peripheral blood lymphocytes [PBL]) Patients. Four patients with elevated serum IgM and low by adhering cells to plastic or Sephadex G-10 (23). To separate IgG and IgA were studied. Patient 1 is a 17-yr-old black B cell-enriched (B) from T cell-enriched (T) fractions, PBL male with congenital deafness, a renal cyst, and recurrent were incubated with aminoethylisothiouronium bromide- fevers. Initial evaluation during a systemic infection with treated sheep erythrocytes (24). After centrifugation on Ficoll- Pseudomonas aeruginosa revealed agranulocytosis, high Hypaque cushions, B cell-enriched fractions (65±12% sIg+ serum IgM, and low serum IgG and IgA (Table I). Skin tests cells, 25% nonspecific esterase+ cells, 2±2% OKT3+ cells) were positive against mumps. He is presently well and being were harvested from the interphase. T cells were collected treated with intravenous gamma globulin. His granulocyte from the pellet after lysis of erythrocytes with NH4Cl buffer levels are now normal. (96±2% OKT3+ cells). Patient 2 is a 2-yr-old black male with a history of re- Cell culture. Total PBL were cultured at 106 cells/ml. current otitis media and upper respiratory infections. During For lymphocyte subpopulations, 5 X 105 cells from the B an episode of pneumonia, he was evaluated for immune fraction were combined with 5 X 105 T cells in 1 ml of deficiency and studies revealed striking neutropenia, ele- medium (RPMI-1640 plus 10% fetal bovine serum, 2 mM L- vated IgM, and depressed IgG and IgA (Table I). Bone mar- glutamine, 50 uM 2-mercaptoethanol, 100 gg/ml strepto- row aspiration showed a promyelocytic arrest, and epineph- mycin sulfate, and 100 U/ml penicillin). Cells were incubated rine and hydrocortisone stimulation tests induced a two- and for 7 d (37°C; humidified 5% C02-air) in the presence or fivefold increase in peripheral neutrophil counts. He is cur- absence of the indicated activator and media were harvested. rently receiving intramuscular gamma globulin, and his neu- In some experiments, cells were collected and prepared for tropenia persists. fluorescent staining. Cells were washed with phosphate-buff- Patient 3 is a 21-yr-old white male with a history of severe ered saline (pH 7.4) containing 0.5% bovine serum albumin infections (Haemophilus influenza meningitis, overwhelm- and 0.01% NaN3, and centrifuged onto glass slides. Cells ing Herpes zoster, pneumococcal meningitis, and osteomy- were fixed in ice-cold 95% ethanol-5% acetic acid for elitis), lymphadenopathy, and splenomegaly since age seven. 15 min. He also experiences severe protein-losing enteropathy as well Quantitation of plasma cell differentiation and Ig se- as anaphylactoid reactions when injected with intramuscular cretion. Fixed cells were stained with fluorescein or rho- gamma globulin. He is currently treated with a different damine conjugates of goat anti-human , y, or a (25). Brightly preparation of gamma globulin intravenously and is doing stained plasma cells were counted on a Leitz (E. Leitz, Inc., well. Rockleigh, NJ) fluorescent microscope and the number of TABLE I Ig Levels and Leukocyte Counts in Patients with Hyper IgM Immunodeficiency Serum Ig Differential Patient IgM IgG IgA Leukocyte PMN Lvmphocytes Monom.tes Eosinophil Basophil mg/dl /mma 1 2,000 <6 <1.2 2,000 75 25 0 0 0 2 175 231 <1.2 14,400 1 86 10 2 1 3 620 63t <2 21,800 48 37 0 12 3 4 600 240t <2 6,400 10 76 10 2 2 PMN, polymorphonuclear leukocyte.