AGA Abstracts producing colonic DC. There were also no significant differences in concentrations of bacterial strains when comparing IL-6 or IL-12p40 positive DC, with IL-6 and IL12p40 negative DC, although the numbers of patients whose DC were negative for these cytokines were small (2 and 4, respectively).CONCLUSION: Increased concentrations of faecal microbiota, in particular bifidobacteria, were associated with the ex vivo production of anti-inflammatory IL-10 by colonic DC, an observation that is consistent with the effects of bifidobacteria on DC In Vitro. Although further work is required before a causal link can be established, these data further suggest the potential of commensal microbiota to modulate the function of intestinal DC. W1202 Helicobacter bilis Infection Alters the Spatial Distribution of Commensal Bacteria in Colitic C3h/Hen Mice Albert Jergens, Todd A. Atherly, Robert T. Doyle, Abigail Henderson, Kelley M. Clausen, Cherie Ziemer, Michael J. Wannemuehler Background: Infection with Helicobacter bilis triggers the immune reactivity to the resident intestinal bacteria that is associated with the development of mucosal inflammation in defined flora C3H mice. Whether perturbations of the commensal microbiota occur and contribute to Helicobacter-induced colitis has not been systematically investigated. Aim: To study the spatial distribution of a defined bacterial population in normal and inflamed murine intestines using fluorescence in situ hybridization (FISH) and to correlate these observations to the development of colitis. Methods: Gnotobiotic C3H/HeN mice harboring the eight members of the altered Schaedler flora (ASF) were selectively colonized with H. bilis. The ASF and H. bilis bacteria were detected in formalin-fixed colonic tissue sections with FISH using 16S ribosomal RNA-targeted probes for all bacteria (EUB338) and specific probes for the major representatives of the ASF (Bacteroides - BAC303, Eubacterium rectale - Clostridium cocco- ides group - EREC482, Lactobacillus - LAB158) as well as for the detection of ASF457 and Helicobacter spp. (HEL717). Each section was evaluated by hyperspectral microscopy. The number of bacteria (total and target groups) and their spatial distribution (mucus-scattered, adherent to epithelia, within mucosa) was randomly determined in thirty 60x fields of tissue and compared between control and infected groups. Results: Total bacterial numbers were increased in H. bilis-infected mice compared to healthy mice. The spatial distribution of bacteria in diseased mice was significantly different with higher numbers of Clostridium (ASF356, ASF500, ASF502) and E. plexicaudatum detected in all compartments, but espe- cially in the mucosa-associated population. Invasive Clostridium spp. were found in both superficial and glandular epithelia, often as bacterial clusters. H. bilis was detected in the free mucus in large numbers but was also shown to be adherent and invasive in H. bilis- colonized mice. ASF 457 was abundant in the mucosa-associated population in healthy mice; additionally these mice also had adherent and sporadic invasive Clostridium spp. Conclusions: FISH provided a specific and cultivation-independent means to investigate the structural relationship between bacteria and the colonic mucosa during the development of experimental colitis. Infection of C3H/HeN mice with H. bilis perturbed the spatial distribu- tion of commensal ASF members whereby increased numbers of adherent and invasive Clostridium spp. might participate in the mucosal inflammatory response. W1203 Despite Mucosal CD4+ T Cell Depletion, the Prevalence of GI Symptoms Is Low During Acute and Early HIV-1 Infection Thomas C. Lee, Saurabh Mehandru, Okebugwu Kamalu, Lisa Malter, Martin Markowitz, Michael A. Poles Background: The gastrointestinal (GI) mucosa is a primary site of viral replication and CD4 depletion after HIV infection. The relationship between mucosal immune dysregulation and the development of GI symptomatology remains unclear. Having established that mucosal CD4 depletion occurs in all patients during acute/early HIV-1 infection, we asked if this correlated with the presence of GI symptoms. In all, we studied 32 patients with acute/ early HIV-1 infection and 38 controls including 24 patients with chronic HIV-1 infection and 14 HIV-uninfected subjects. Methods: Rectosigmoid colonic mucosal tissue, obtained endoscopically, and peripheral blood were utilized to determine the percentage of CD4+ T cells and CD4:CD8 ratio in each site by flow cytometry. GI symptomatology, including diarrhea, nausea, and abdominal pain were noted at the time of endoscopic examination. Correlation was sought between the presence of GI symptomatology and virologic and immunologic parameters. Results: The acutely-infected subjects underwent endoscopy a mean of 38.5 days after their estimated date of HIV-1 infection, well after resolution of acute retroviral syndrome, while the patients with chronic infection were diagnosed with HIV-1 a mean of 7.3 years at the time of endoscopy. Only 3 of 32 acutely-infected subjects and 2 of 24 chronically-infected subjects were receiving antiretroviral medications at the time of study. Severe mucosal CD4+ T cell depletion was seen in both acute and chronic infection cohorts with mean mucosal CD4:CD8 ratios of 0.29 and 0.08 (HIV negative controls= 1.3). Despite significant mucosal depletion in acute infection patients, diarrhea, abdominal pain and nausea were only seen in 6.25%, 0% and 6.25% of patients respectively. In comparison, these symptoms were experienced by 62.5%, 37.5% and 33.3% of chronically- infected patients. Factors associated with the development of diarrhea included the presence of chronic HIV-1 infection, and a past history of opportunistic infections. While the degree of plasma viremia did not correlate with the presence of diarrhea, both mucosal and systemic CD4:CD8 ratios T cell did. The presence of diarrhea was more highly correlated with the blood CD4:CD8 ratio, as compared to that of the mucosa. Conclusions: Despite severe mucosal CD4+ T cell depletion, GI symptomatology is rarely seen during the acute/early HIV-1 infection period after the acute retroviral syndrome. However, a significant percentage of patients with chronic HIV-1 infection appear to develop GI symptoms. Development of GI symptoms correlates more strongly with the degree of systemic rather than GI mucosal immune depletion. A-654 AGA Abstracts W1204 Association of Serum Levels of Ficolin-2 and Ficolin-3 with Bacterial and Yeast Antigens and Distinct Crohn's Disease Phenotypes Alain Schoepfer, Thomas Schaffer, Stefan Mueller, Beatrice Seibold-Schmid, Frank Seibold Background: Ficolins, an important part of the innate immune system, are complement activating soluble pattern recognition molecules. A dominant recognized epitope is N-acetyl- glucosamine which is found in the cell wall of bacteria and yeasts. Ficolin-2 (expressed by liver) and ficolin-3 (expressed by liver/lung) are found in serum/plasma. The role of ficolins in Crohn's disease (CD) is largely unknown. Aim: Evaluation of the significance of ficolins in IBD and its association with CD phenotypes and serological markers such as ASCA, and antibodies to flagellin. Methods: Serum concentrations of ficolin-2 and ficolin-3, ASCA, and Anti-A4-Fla2 antibodies (all ELISA) were measured in 182 CD patients, 67 patients with ulcerative colitis (UC) and 67 healthy controls (HC). CD patients were classified into the following phenotypes: nonstricturing-nonpenetrating (n=72, 40%), stricturing (n=64, 35%), and penetrating (n=46, 25%). Results: Serum levels of ficolin-2 were significantly higher in CD (1683±878ng/mL) and UC (1480±843ng/mL) compared to HC (1170±765ng/mL) (P<0.0001 and P=0.028). Serum levels of ficolin-3 in CD patients (22659±10606) were not different from HC (24265±9690ng/mL). UC patients had lower ficolin-3 levels (21288±7582ng/mL) compared to HC (P=0.037). Serological profiles: Positivity for A4-Fla2 and ASCA (in percent): 57/63 in CD patients, 6/4 in UC patients, and 1/4 in HC. For quantitative analysis, we distributed ficolin levels into normal (within the 95%-confidence interval), high (>95%-CI) and low (<95%-CI), and the ASCA and A4-Fla2 titers into low, intermediate and high positive according their extinction. CD patients with intermediate/ high ASCA titers had significantly lower ficolin-2 levels (P=0.044) compared to ASCA low positive and ASCA negative CD patients. CD patients with intermediate/high ASCA titers had significantly lower ficolin-3 levels (P=0.0093) compared to ASCA negative CD patients. We found no association between ficolin-2 and ficolin-3 levels and Anti-A4-Fla2 antibodies as well as distinct CD phenotypes. Conclusions: CD patients have significantly higher ficolin- 2 levels compared to HC, possibly reflecting ficolin-2 - but not ficolin-3 - upregulation during inflammatory conditions. The association of high ASCA titers with low ficolin-2 and ficolin-3 levels may indicate reduced clearance of GlcNAc-carrying antigens such as yeast mannans. In contrast, ficolin-levels are not (negatively) associated with antibodies against bacterial flagellin and do not correlate with a distinct CD phenotype. W1205 Eosinophils in Chronic Gastritis: Possible Implications in Carcinogenesis M. Blanca Piazuelo, M. Constanza Camargo, Robertino M. Mera, Alberto Delgado, Richard M. Peek, Hernan Correa, Barbara G. Schneider, Liviu A. Sicinschi, Yolanda Mora, Luis E. Bravo, Pelayo Correa Background: Eosinophils, classically recognized for their role in allergic reactions and parasitic infections, are being increasingly studied in a wide range of processes. In the gastric mucosa, eosinophils participate in the immune response against Helicobacter pylori, but their involvement in the precancerous process is unclear. We hypothesize that eosinophils, being part of an anti-inflammatory Th2-type response, may protect the gastric mucosa against cancer development. This study aimed to estimate eosinophil density in antral mucosa in subjects from two Colombian populations with contrasting gastric cancer risks. Methods: Gastric mucosa biopsies were collected from 117 adult males (40-59 years old) with dyspeptic symptoms (72 from a high-risk area for gastric cancer and 45 from a low-risk area). Histopathological diagnosis and quantitation of eosinophils was performed in hematoxylin- eosin stained sections. H. pylori infection was assessed by PCR. Results: H. pylori infection prevalence was 93% and 90% in low- and high-risk areas, respectively (p=0.739). Overall, median values of eosinophil density (eosinophils/mm 2 ) in the antral mucosa were significantly higher in subjects from the low-risk area compared with those from the high-risk area (63.5 and 24, respectively; p<0.001). Conclusion: The elevated eosinophil density observed in early stages of the precancerous process (non-atrophic gastritis and MAG) in the low-risk area may reflect a strong anti-inflammatory Th2-type immune response to H. pylori that may dampen the progression to more advanced stages. a This value is not a median, it is the eosinophil density of the only subject in that category. b There were only 2 subjects with dysplasia in each risk area, both displayed also IM. Abbreviations: NAG: non-atrophic gastritis; MAG: multifocal atrophic gastritis without meta- plasia; IM: intestinal metaplasia; IQR: interquartile range. W1206 Impaired Sulphide Detoxification in Ulcerative Colitis Is Related to Inflammation Vicky De Preter, Ingrid Arijs, Els Houben, Paul J. Rutgeerts, Kristin Verbeke Introduction: The colonic mucosa is exposed to large quantities of H 2 S, a metabolic product of the colonic microbiota. Defective detoxification of sulphides leads to damage to the mucosa and has been suggested to play a role in the aetiology of ulcerative colitis (UC). The colonic mucosal thiosulfate sulfurtransferase (TST) enzyme has been shown to remove