Distinct patterns of IgG and IgA against food and microbial antigens in serum and feces of patients with inflammatory bowel diseases.

BACKGROUND: Inflammatory bowel disease (IBD) is associated with a defective intestinal barrier and enhanced adaptive immune responses against commensal microbiota. Immune responses against food antigens in IBD patients remain poorly defined. METHODS: IgG and IgA specific for food and microfloral antigens (wheat and milk extracts; purified ovalbumin; Escherichia coli and Bacteroides fragilis lysates; mannan from Saccharomyces cerevisiae) were analyzed by ELISA in the serum and feces of patients with Crohn's disease (CD; n = 52 for serum and n = 20 for feces), ulcerative colitis (UC; n = 29; n = 17), acute gastroenteritis/colitis (AGE; n = 12; n = 9) as well as non-inflammatory controls (n = 61; n = 39). RESULTS: Serum anti-Saccharomyces cerevisiae antibodies (ASCA) and anti-B. fragilis IgG and IgA levels were increased in CD patients whereas antibody (Ab) levels against E. coli and food antigens were not significantly different within the patient groups and controls. Subgroup analysis revealed that CD patients with severe diseases defined by stricturing and penetrating lesions have slightly higher anti-food and anti-microbial IgA levels whereas CD and UC patients with arthropathy have decreased anti-food IgG levels. Treatment with anti-TNF-α Abs in CD patients was associated with significantly decreased ASCA IgG and IgA and anti-E. coli IgG. In the feces specific IgG levels against all antigens were higher in CD and AGE patients while specific IgA levels were higher in non-IBD patients. Anti-food IgG and IgA levels did not correlate with food intolerance. SUMMARY: In contrast to anti-microbial Abs, we found only minor changes in serum anti-food Ab levels in specific subgroups of IBD patients. Fecal Ab levels towards microbial and food antigens show distinct patterns in controls, CD and UC patients.

Assessment of inflammatory and fibrotic stenoses in patients with Crohn's disease using contrast-enhanced ultrasound and computerized algorithm: a pilot study.

PURPOSE: The development of stenosis is a typical complication of Crohn's disease and represents a serious diagnostic and therapeutic challenge. The aim of the present study was to define objective quantitative measures of stricture characteristics (fibrostenotic/cicartricial vs. inflammatory) using contrast-enhanced ultrasound (CEUS) in patients with stenotic Crohn's disease. MATERIALS AND METHODS: During a period of 18 months, 18 consecutive patients with Crohn's disease and manifestation of a localized significant small bowel stenosis were prospectively recruited. Standardized ultrasound (US) examination, color-coded duplex sonography and CEUS using SonoVue® were performed. Quantitative measurements of bowel wall vascularity were determined using computerized algorithms (Bracco QONTRAST software). The quality of stenosis (fibrostenotic vs. inflammatory) was classified in a 4-point scale, and the diagnostic/prognostic power of the US and clinical tests upon initial presentation were compared. RESULTS: We established a novel standardized CEUS procedure using computerized algorithms to quantitatively examine stenoses in Crohn's disease. An inflammatory origin of stenosis correlated significantly with a high Crohn's Disease Activity Index (CDAI) (p < 0.01), the length of stenosis (p < 0.01) as well as the Limberg score (p < 0.01). There was no correlation between the type of stenosis and quantitative results of CEUS. CONCLUSION: Although bowel wall vascularity can be quantitatively assessed in stenotic areas by CEUS, this analysis does not improve the diagnostic power for the objective determination of the quality of stenosis at a single measurement. Semiquantitative analysis of bowel wall vascularity, length of stenosis, and CDAI may help to discriminate the origin of small bowel stenosis in Crohn's disease.