A800 AGA ABSTRACTS GASTROENTEROLOGY, VoI. IO8, No. 4

EVIDENCE FOR A SPECIFIC ANTIBODY RESPONSE TO SACCHAROMTCES CEREVISIAE OLIGOMANNOSIDIC EPITOPES IN CROHN'S DISEASE. J.F.Colombel (1), B.Scndid (2), P.M.Jaequinot (3), A.Cortot (1), D.Camus (2,3), D.Poulain (2,3). Service d'H6pat o-gastroent6rologie CHRU Lille (1); Laboratoire de Parasitologie-Mycologie, Facult6 de M6decine Lille (2); INSERM U42, Lille, France (3).

Background/Alms: Elevated antibody levels against the yeast Saccharomyces eerevisiae have been reported in sera of patients with Crohn's disease (CD) and not ulcerative colitis (UC). The aim of this study was to identify the nature of the epitopes stimulating this antibody response.

Methods: Whole cells from different S. cerevisiae strains were selected in immunofluoreseance assays for their ability to differentiate the antibody responses of CD and UC patients. Their cel l wall phosphopeptidomannans (PPM) were then tested as antigen in ELISA against sera from 42 patients with CD, 20 patients with UC and 34 healthy controls. Graded chemical degradations were then performed on the most reactive strain. The domain of the molecule bearing the discriminating epitopes was determined through gas-liquid chromatography-mass spectrometry.

Results: The greatest discrimination between patients with CD and UC was obtained with Saccharomyces uvarum 1 (Sul), a S. cerevisiae strain used in the brewing of beer. ELISA directed against Sul PPM was 64% ' sensitive and 77% specific discriminating CD vs UC and 71% sensitive and 89% specific for CD vs controls. Periodic oxidation and selective degradation demonstrated that the polysaccharide epitope of importance was shared by both the acid stable and alkali labile domains of the PPM. Determination of oligomannose sequences of Sul PPM suggests that a mannotetrose Man(I--,.3) Man(I-,2) Man(I---,2) Man was responsible for the serological response seen in CD.

Conclusion: An antibody response against a sequence of mannose residues was specifically associated with CD. Further identification of this immunogen may help to understand its potential as a disease marker and why this response occurs at all.

• HLA CLASS H GENES AND CROHN'S DISEASE : DIFFERENT ASSOCIATIONS IN ADULTS AND CHILDREN. JF Colombel. PM Danz6, S Jacquot, MN Loste, D Heresbach, S Ategbo, B P6richon, G Semana, JP C6Zard. CHRU Lille, St-Louis-Paris, R.Debr6-Paris et Rennes; CRTS Rannes et INSERM U120, Paris, France.

Available studies of association between HLA class II genes and Crohn's disease (CD) have given various results. Those discrepancies might be partly due to heterogeneity in age of studied patients.

The aim of the study was to measure frequencies of HLA class II genes among two different populations of patients with CD diagnosed when adult (>16 years) or during childhood (< 16 years).

Methods : 258 adults (137 F, 121 H, mean age 22 years) and 75 children with CD (35F, 40H, mean age 11.5 years) had molecular genotyping of HLADQA1, DQB1 and DRB1 alleles using molecular biology (PCR-SSO or PCR'RFLP). The results were compared in an ethnically matched control population of 486 caucasian adults using Chi2 test with p corrected value.

Results : Different genes frequencies i n the 3 groups (in %) : Adults with CD Children with CD Controls

~n = 258) (n= 75) ~n = 486) DQB1*0602.3 12.8%* 16.2% 19%

14.7% 19.7%* 10.2% DOBI*0501 DRB1*01 14.6%$ 16.2%$ 9%

13.3% DRBI*03 6.5%* 5.6%$ DRBI*07 17.6%§ 12.7% 11.1%

* : p<0.025 vs Controls; $ : p<0.01 vs Controls; § : p<0.001 vs Controls. Conclusion : There was a positiveassociation between DRBI*01 gane

and a negative association between DRB1*03 gene and CD in both adults and children. Different associations observed between DQB1 and DRBI*07 genes in children and adults suggest that those genes may influenCe the age of onset of CD.

• SERUM TRANSFERRIN RECEPTOR/FERHITIN RATIO IS A RELIABLE PREDICTOR OF IRON DEFICIENCY ANEMIA IN INFLAMMATORY BOWEL DISEASE PATIENTS. C. colton r K. Geraci, H. Tahsildar, C. Flowers, J. Cook, G. Cooper, K. Hornbuckle. Depts. of Medicine, Case Western Reserve Univeristy, Cleveland, OH and Kansas University, Kansas City, Kansas. Background~Aims: Iron studies are difficult to interpret in chronic disease states such as inflammatory bowel disease(IBD). Recently, the serum Transferrin Receptor/Ferritin ratio(TRF) has been reported to be a reliable indicator of iron deficiency. The aim of this study is to determine if the TRF is a reliable predictor Of iron deficiency in IBD. Methods: 18 consecutive IBD patients with anemia(Hct.<35%) were asked to participate; 16 consented. Two patients were excluded(serum lost in one patient, hemolysis in the second patient), leaving 14 participants. There were 8 patients with ulcerative colitis(UC) and 6 with Crohn's~ disease(CD); 4 were male and 10 were females. The mean age was 52. Serum iron, transferrin saturation, ferritin, transferrin receptor level(TR) Via ELISA, and bone marrow biopsy were obtained from each. The TRF was calculated by the formula: (TR/ferritin)x1000. Activity of disease was determined by flexible sigmoidoscopy in UC and by the Harvey-Bradshaw index in CD. Results: By bone marrow biopsy 10 patients had no iron stores , and 4 patients had elevated iron stores. The mean TFR was 53.1 in those with elevated iron stores and 1314.0 in iron deficient patients(p=0.009 by Wilc0~on analysis). Positive Negative

PredictivePredictive Sens. Spee. Value Value

Ferritin(<15u~/dl) 50% 100% 100% 33% TRF(>I00) 90% 100% 100% 80% Conclusions: The TRF is a reliable predictor of iron deficiency in IBD patients, and is more sensitive than serum ferritin in these patients.

T LYMPHOCYTE SUBSETS IN GASTRIC TISSUE ARE ALTERED IN THE PRESENCE OF HELICOBACTER PYLORI. C.Colton t S.Czinn, S.Setrakian, M.Sy, A.Chak, K.Ferguson. Depts. of Medicine, Pediatrics and Pathology. Case Western Reserve University, Cleveland; OH. Background/Aims: The pathogenesis of inflammation in tissue infected by H. pylorl has not been completely elucidated. The aim of this study is to determine T helper(CD4) and T cytolytic(CD8) lymphocyte density and ratios in gastric tissue infected by H. py!ori as compared to control tissue. Methods: Antral biopsies were obtained from patients undergoing routine endoscopy. The presence of H. pylori was determined by Hematoxylin and Eosin and Giemsa stains. The lamina propria of frozen tissue sections were examined using an immunohistochemical assay, labelled streptavi- din-biotin(LSAB), to visualize CD4 and CD8 molecules microscopically. Results: Biopsy speci- mens were obtained from 20 patients. Tissue sections from 3 controls with normal tissue histo- logically had a mean of 2.3 CD4 and 2.6 CD8 cells per high power field(HPF) by LSAB. 10 tissue sections with chronic inflammation without H. pylori had a mean of 18.2 CD4 and 12.1 CD8 cells per HPF. Mean CD4:CD8 ratio for these patients was 1.53(range 0.3-2.5). For the 7 patient~ with chronic inflammation and ~. pylori present the mean CD4 and CD0 ce!l count~ per EPF were 13.2 and 17.9 respectively. Mean CD4:CD3 ratio for these patients was 0.82(range 0.1-0.9). The difference between CD4:CD8 ratios for the two groups with chronic inflammation was statistically significant by Wilcoxon analysis(p=0.03). Conclusions: CD4 and CD8 cells playa role in the inflammatory response of H. pylori infected tissue, and theirratio as compared to inflammed tissue without H. pylori is reversed. This suggests a more prominent role of CD8 lymphocytes in H. pylori infected tissue as compared to inflammed control tissue.