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The Frequency of Lymphocytic Gastritis in Baboons

CARLOS A. RUBIO, EDWARD J. DICK Jr. and GENE B. HUBBARD

Southwest National Primate Research Center, Southwest Foundation for Biomedical Research, San Antonio, TX, 78245-0549, U.S.A.

Abstract. Background: In 1985, two independent reports a benign gastric ulcer”. In a subsequent publication (3) we highlighted a novel subtype of chronic inflammation in the reported in electron microscopic studies that these "in halo" , characterized by the intraepithelial lymphocytic cells had the ultrastructural characteristics of lymphocytes. infiltration (ILI) both in the surface and the foveolar "In halo" lymphocytes were found in the subnuclear aspect . The disease, subsequently called lymphocytic of the foveolar cytoplasm, even in areas without gastritis (LG) is a rare form of gastritis (0.8%-1.6% of cases), inflammation in the . with unclear pathogenesis. More recently, LG was recorded in In 1988, Haot et al. (4) proposed the term lymphocytic pigs and in non-human primates. Materials and Methods: The gastritis, a term that has prevailed ever since in the English frequency of LG (>25 lymphocytes/100 epithelial cells) was literature. Lymphocytic gastritis (LG) is a rare form of gastritis assessed in gastric specimens from 92 consecutive baboons, (0.8%-1.6% of cases) with unclear pathogenesis (5) initially filed under the diagnosis of “gastritis”. Results: LG was characterized by the intra-epithelial lymphocytic infiltration of found in 13 (14%) out of the 92 animals. Helicobacter pylori the surface and the foveolar epithelium (>25 lymphocytes/100 was not found. Discussion: LG mirrors an immunological epithelial cells). phenomenon at the surface-foveolar cell level elicited by an In a study of 48 entire gastrectomies carrying a carcinoma uncertain etiological factor. In similarity to humans with LG, (6) we found LG in two specimens. All 156 sections in the no Helicobacter pylori were found in baboons with LG. The two specimens showed LG, even in areas lacking chronic search for the lymphocyte-attracting protein contained in mucosal inflammation in the lamina propria mucosa (lpm). affected cells might bring forward an alternative therapy Whereas specimens with “conventional” chronic gastritis capable of abrogating the specific surface-foveolar cell- demonstrated that the inflammation in the lpm had a focal lymphotaxis present in LG. The baboon emerges as a possible distribution, specimens with LG showed a continuous animal model to study the agent(s) leading to LG. lymphocytic infiltration of the surface and foveolar epithelium in all 156 sections. In 1985, two independent reports highlighted a novel It should be pointed out that LG might also be found in subtype of chronic inflammation in the gastric mucosa, areas with hypertrophic mucosal folds. Studies of 13 characterized by the infiltration of lymphocytes both in the gastrectomy specimens (7) demonstrated in 5 specimens surface and the foveolar epithelium (1, 2). This subtype of with diffuse hypertrophic fundic mucosal folds at gross gastric chronic inflammation received trivial names, such as examination, that 3 were Ménétrier-like LG (with marked the lympho-epithelial phenomenon of the gastric mucosa (1) intraepithelial lymphocytosis) and the other 2, Ménétrier's and la gastrite à lymphocytes, respectively (2). gastropathies (without intraepithelial lymphocytosis). Of the In our initial communication (1), we wrote: “Lymphocyte- 6 specimens with multiple mucosal nodules at gross like cells surrounded by a clear halo were found within the examination, 2 were varioliform-like LG, and the other 4 surface-foveolar epithelium both in the fundus and the were varioliform gastropathies (without intraepithelial antrum in a gastrectomy specimen containing concomitantly lymphocytosis). In the remaining 2 cases, having both diffuse and nodular hypertrophic gastric mucosa at gross examination, we found hyperplastic LG at (7). LG is not a disease exclusive to humans. In earlier Correspondence to: C.A. Rubio, MD, Ph.D., Gastrointestinal and investigations we found that LG occurred spontaneously in Liver Pathology Research Laboratory, Department of Pathology, the gastric mucosa of pigs (8). More recently we detected Bldg P1/R8:02, Karolinska Institute and University Hospital, 17176, LG in the gastric mucosa of 3 baboons (9). This latter Stockholm, Sweden. Fax: 46 8 51774524, e-mail: [email protected] finding prompted us to investigate the frequency of LG in Key Words: Lymphocytes, gastritis, frequency, baboons, non-human the stomachs in a consecutive cohort of baboons with primates. gastritis.

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Table I. The frequency of different histological subtypes of gastritis (including lymphocytic gastritis) in 92 gastric specimens from baboons dying of natural causes between 1996 and 2006, filed initially under the diagnosis of “gastritis” at histological examination.

Histology No. of cases (%)

Acute inflammation 3 (3.3%) Superficial gastritis 12 (13.0%) Chronic antritis 26 (28.3%) Chronic corpitis 18 (19.6%) Atrophy in the corpus due to chronic inflammation 8 (8.7%) Atrophy in the antrum due to chronic inflammation 5 (5.4%) Follicular gastritis 7 (7.6%) Figure 1. Superficial chronic gastritis in a baboon (H&E). Lymphocytic gastritis 13 (14.1%) All 92 (100%)

Materials and Methods

The baboons were members of colonies at the Southwest National Primate Research Center, Southwest Foundation for Biomedical Research, San Antonio, TX, USA. The Interdisciplinary Principles and Guidelines for the Use of Animals in Research, Testing, and Education were applied (10). The conditions of animal housing have been reported elsewhere (10). Briefly the baboons were housed in metal and concrete Figure 2. Folicular gastritis in a baboon (H&E). indoor-outdoor cages and were fed commercial monkey diets occasionally supplemented with a variety of fruit and vegetables. Water was available ad libitum. Baboons were euthanized with a commercial barbiturate agent Discussion because of non-GI diseases or natural causes such as old age. All procedures were performed in accordance with the Institutional In the present survey, 14% of gastric specimens from Animal Care and Use Committee guidelines (11). At necropsy, longitudinal tissue samples from the consecutive baboons having an initial diagnosis of “gastritis” were fixed in 10% neutral-buffered formalin, processed at histological examination had LG. This percent is up to 10 conventionally, embedded in paraffin, cut at 5 Ìm, stained with times higher than the percentage of LG reported in humans, hematoxylin and eosin (H&E), and evaluated by light namely 0.8%-1.6% (12). microscopy. Several authors claim that Helicobacter pylori is the A total of 92 well-preserved gastric specimens from baboons etiological agent of LG in humans (5, 13). However, H. dying of natural causes between 1996 and 2006, filed initially under pylori infection was found in only 4 out of 21, in none out the diagnosis of “gastritis” at histological examination, were reviewed. LG in baboons was defined as the intraepithelial of 5, and in 4 out of 7 cases with LG (14-16, respectively). In infiltration of the surface and the foveolar epithelium of the gastric one of our studies (17), no Helicobacter pylori was found in mucosa by >25 lymphocytes. any of the 156 Giemsa-stained sections taken from the two gastrectomy-specimens showing LG. Results In the present work, no Helicobacter pylori were found in the gastric mucosa of baboons having LG. In fact, the The results in Table I show that LG occurred in 13 (14%) scrutiny of H&E sections of the 13 cases of LG revealed out of the 92 animals. The Table also shows that various structures compatible with H. pylori in only one. The subtypes of acute and chronic gastric inflammation also staining of parallel sections with Giemsa stain, however, was occurred in the gastric mucosa in baboons. Some of these negative for H. pylori. subtypes are illustrated in Figures 1-3. For comparison, the The prevalence of the H. pylori infection in gastric normal mucosa of the antrum and the corpus in other biopsies with patients with dyspepsia varies from country to baboons are shown in Figures 4 and 5. country, from 82% in Yemen (18) to 30% in Germany (5).

102 Rubio et al: Lymphocytic Gastritis in Baboons

Figure 4. Normal antral mucosa in a baboon (H&E).

Figure 3. Lymphocytic gastritis in a baboon (H&E).

Figure 5. Normal fundic mucosa in a baboon (H&E).

In the light of this knowledge, several questions arise: i) If H. pylori causes LG (5, 13, 19) why are there no reports indicating that the prevalence of this condition is higher in The search for the lymphocyte-attracting protein countries with a high prevalence of H. pylori? ii) If H. pylori contained in affected cells might bring forward an causes LG, why is intraepithelial lymphocytosis of the surface- alternative therapy capable of abrogating the specific foveolar epithelium of the so rare among patients with surface-foveolar cell-lymphotaxis. the more common form of H. pylori-induced gastritis (17, 20) Since the etiological factor responsible for this disease characterized by a high number of lymphocytes in the Lamina remains uncertain, the baboon emerges as a possible animal propria mucosa (lpm)? iii) If H. pylori causes LG in baboons, model to study the cause(s) leading to LG, a disease also why are the bacteria not detected in Giemsa stains (a common affecting humans. marker for H. pylori in routine gastric biopsies in humans)? LG may concur with other conditions showing References intraepithelial lymphocytosis, such as celiac disease and lymphocytic colitis (16, 19, 21, 22), implying that in these 1 Rubio CA, Kato Y and Sugano H: The lymphoepithelial patients, the intraepithelial lymphocytosis is elicited, phenomenon in the gastric mucosa. Path Res Pract 180: 612- simultaneously, in the absence of H. pylori in the small and 614, 1985. large intestines. 2 Haot J, Wallez L, Jouret-Mourin A and Hardy N: La gastrite The absence of H. pylori bacteria in baboons with LG “à lymphocytes”. Une nouvelle entité? Acta Endoscopica 15: suggests that cause(s) other than H. pylori might be 187-188, 1985. responsible for the development of the intraepithelial 3 Rubio CA, Ost A and Larsson B: The lymphoepithelial phenomenon of the stomach. A case report. APMIS 96: 898- inflammatory process in the gastric mucosa. 900, 1988. In our initial work (1) we suggested that LG might mirror 4 Haot J, Hamichi L, Wallez L and Mainguet P: Lymphocytic an immunological phenomenon at the surface-foveolar cell gastritis: a newly described entity: a retrospective endoscopic level elicited by an elusive etiological factor. and histological study. Gut 29: 1258-1264, 1988.

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5 Müller H, Rappel S, Volkholz H and Stolte M: Lymphocytic 16 Feeley KM, Heneghan MA, Stevens FM and McCarthy CF: gastritis, a rare disorder of the gastric mucosa. Pathologe 22: Lymphocytic gastritis and coeliac disease: evidence of a positive 56-61, 2001. association. J Clin Pathol 51: 207-210, 1998. 6 Rubio CA, Befritz R, Eriksson B, Christensson B, Duvander A 17 Befrits R, Granstrom M, Rylander M and Rubio CA: and Larsson B: The topographic distribution of lymphocytic Helicobacter pylori in 205 consecutive endoscopy patients. Scand gastritis in gastrectomy specimens. APMIS 99: 815-819, 1991. J Infect Dis 25: 185-191, 1993. 7 Rubio CA, Ost A, Kato Y, Yanagisawa A, Rivera F and Hirota 18 Gunaid AA, Hassan NA and Murray-Lyon IM: Recurrence of T: Hyperplastic foveolar gastropathies and hyperplastic foveolar Helicobacter pylori infection 1 year after successful treatment: gastritis. APMIS 105: 784-792, 1997. prospective cohort study in the Republic of Yemen. Eur J 8 Rubio CA, Jarlnas M and Johnson L: Animal model of human Gastroenterol Hepatol 16: 1309-1314, 2004. disease: lymphocytic gastritis. In Vivo 7: 457-459, 1993. 19 Niemela S, Karttunen T, Kerola T and Karttunen R: Ten year 9 Rubio CA and Hubbard G: Hyperplastic foveolar gastropathy follow up study of lymphocytic gastritis: further evidence on and hyperplastic foveolar gastritis in baboons. In Vivo 10: 507- Helicobacter pylori as a cause of lymphocytic gastritis and corpus 510, 1996. gastritis. J Clin Pathol 48: 1111-1116, 1995. 10 Bayne K: Developing Guidelines on the Care and Use of 20 Su B, Hellström P, Rubio CA, Celikm J, Granström M and Animals Annals NY Acad Sci 862: 105-110, 1998. Normark S: Helicobacter pylori (type I) shows Lewisb 11 Barrier BF, Dick EJ Jr, Butler SD and Hubbard GB: independent adherence to gastric cells requiring de novo Endometriosis involving the ileocaecal junction with regional protein synthesis in both host and bacteria. J Infect Diseases lymph node involvement in the baboon striking pathological 178: 1379-1390, 1998. finding identical between the human and the baboon: a case 21 Perardi S, Todros L, Musso A, David E, Repici A and Rizzetto report. Hum Reprod 22: 272-274, 2007. M: Lymphocytic gastritis and protein-losing gastropathy. Dig 12 Magalhães Queiroz DM and Luzza F: Epidemiology of Liver Dis 32: 422-425, 2000. Helicobacter pylori infection. Helicobacter Suppl 1: 1-5, 2006. 22 Karttunen T and Niemela S: Lymphocytic gastritis and coeliac 13 Makinen JM, Niemela S, Kerola T, Lehtola J and Karttunen disease. J Clin Pathol 43: 436-437, 1990. TJ: Epithelial cell proliferation and glandular atrophy in lymphocytic gastritis: effect of H. pylori treatment. World J Gastroenterol 9: 2706-2710, 2003. 14 Wu TT and Hamilton SR: Lymphocytic gastritis: association with etiology and topology. Am J Surg Pathol 23: 153-158, 1999. 15 Drut R and Drut RM: Lymphocytic gastritis in pediatric celiac Received October 23, 2007 disease-immunohistochemical study of the intraepithelial Revised November 29, 2007 lymphocytic component. Med Sci Monit 10: 38-42, 2004. Accepted December 17, 2007

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