Objectives Non-invasive, sensitive and specific tools for early identification of chronic inflammatory bowel diseases (IBD) are needed for clinical practice. The aim was to identify new non-invasive test combinations for characterization of IBD in children and adolescents by comparing serological responses to microbial antigens and fecal calprotectin, a new promising marker for intestinal inflammation. Patients and methods Our study included 73 children who underwent endoscopies because of suspicion of IBD. Their sera were tested for antibodies to the Pseudomonas fluorescens-associated sequence I2, a Bacteroides caccae TonB-linked outer membrane protein, OmpW and anti-Saccharomyces cerevisiae (ASCA). Simultaneously, samples for fecal calprotectin measurements were obtained from 55 subjects. Results IBD was diagnosed in 60 patients (CD in 18 patients, UC in 36 and IC in six). Thirteen children had a non-IBD disease. Fecal calprotectin levels were elevated (≥ 100ug/g) more frequently in IBD patients (89%, 39/44) compared to non-IBD cases (9%, 1/11, p<0.001). ASCA antibodies in sera were detected in 67% (12/18) of patients with CD, in 14% (5/36) of the children with UC and in 50% (3/6) of patients with IC. Seroreactivity for I2 was observed in 42% of the IBD patients, this frequency being higher than in non-IBD cases (7,7% seropositive; p=0.025). Serum anti-I2 IgA levels (median absorbances) were higher in those with IBD compared to those without gut inflammation (p=0.039). The combination of the measurements of fecal calprotectin and serological responses to microbial antigens (ASCA, I2 and OmpW) identified 100% of CD patients (sensitivity 100%, specificity 36%, PPV 66%, NPV 100%) and 89% of UC patients (sensitivity 89%, specificity 36%, PPV 77%, NPV 57%). Conclusions Increased levels of serological responses to microbial antigens (ASCA, I2 and OmpW) and fecal calprotectin are evident in both CD and UC patients. The combination of these markers provides valuable, non-invasive tools for the diagnostics of IBD.

Background Immunoglobulin A (IgA) autoantibodies to tissue transglutaminase (tTG) are commonly used for screening and diagnosing of celiac disease (CD). Seroreactivity for anti-Saccharomyces cerevisiae antibody (ASCA) and bacterial antigens have also been detected in CD patients. The aim of this study was to examine prospectively serologic responses to microbial targets in adult CD patients at the time of diagnosis and during a gluten-free diet (GFD). Further, we wanted to evaluate whether these serologic specificities could provide new tools for the follow-up of CD patients. Methods Data on 55 adult biopsy-proven CD patients were available for follow-up study. Upper gastrointestinal endoscopy was performed on all patients. Sera from patients were tested for antibodies to tTG and ASCA and additionally analyzed with IgA enzyme-linked immunosorbent assays to Pseudomonas fluorescens-associated sequence, I2, and to a Bacteroides caccae TonB-linked outer membrane protein, OmpW. Results At the time of diagnosis, 91% of CD cases were positive for tTG and 49% for ASCA; positive seroreactivity to I2 was found in 86% and to OmpW in 60% of CD patients at the time of diagnosis. The frequency of seropositivity and serum levels of these antibodies decreased during GFD. Moreover, we found that the decline in the serum levels was significant in all of these markers (p<0.005). Interestingly, we also found that serum levels of ASCA correlated with the grade of mucosal morphology (p=0.021), as the ASCA serum levels declined in accordance with mucosal healing. Conclusions Commensal enteric bacteria seem to play a role in the small intestinal mucosal damage in CD. This was proven by the serological responses to different microbial antigens shown in this study. Serum levels of ASCA, anti-I2, and anti-OmpW antibodies decreased significantly during GFD, indicating that these serologic markers are gluten dependent in CD patients. These specificities could provide new tools in the follow-up of CD patients.

Objectives-Expression of anti-Saccharomyces Cerevisiae antibodies (ASCA) identifies patients and individuals at risk for Crohn's disease and has also been reported in 40-60% of Celiac disease (CD) cases, suggesting a role of host response to enteric microbiota in the development of inflammatory lesions. In this prospective study in patients with suspicion of CD, we evaluate the frequency and association of ASCA to serological responses for other host microbial targets formally associated with Crohn's disease, including the P.fluorescens associated sequence I2 and a Bacteroides caccae TonB-linked outermembrane protein, OmpW.Methods-Small bowel mucosal biopsies were taken from 242 patients with CD suspicion, their sera were tested for antibodies to tissue transglutaminase (tTG), ASCA, I2 and OmpW. 80 adult healthy blood donors were used as controls.Results-The diagnosis of CD was confirmed on biopsy in 134 cases. The occurence of ASCA and I2 positivity was significantly higher in adult CD patients as compared to patients with non-CD disease. Anti-I2 levels in the sera were significantly higher in adult CD patients compared to non-CD disease or the controls and anti-OmpW levels in CD and non-CD patients when compared to controls. Positive seroreactivity to OmpW seemed to increase with the age. 90% of CD patients were seropositive for at least one microbial antigen tested.Conclusions-This study demonstrates a mosaic of disease-related serological responses to microbial antigens in patients with CD. Immune responses to commensal enteric bacteria may play a role in the small intestine mucosal damage in CD.

Background and Goals Seroreactivity against the Saccharomyces cerevisiae (ASCA), Pseudomonas fluorescens-associated sequence (I2) and Bacteroides caccae TonB-linked outer membrane protein (OmpW) has been detected in celiac disease patients with small-bowel mucosal atrophy. Levels of these antibodies decrease during a gluten-free diet, but their functions and time of appearance in celiac disease is not known. We aimed to search for evidence of possible microbial targets of the immune responses in the early stage celiac disease patients who showed normal small-bowel mucosal architecture at the time of the first investigations, but later on a gluten-containing diet developed mucosal atrophy. Methods 44 cases with proven early stage celiac disease and normal mucosal morphology were enrolled. Patients’ sera were tested for celiac disease antibodies against tissue transglutaminase (tTG-ab), endomysium (EmA) and for microbial antibodies against I2, OmpW and ASCA IgG and IgA isotypes in both at the time of diagnosis and while on a gluten-free diet. Results 34 (77%) out of 44 patients with early stage celiac disease had elevated serum antibodies to one or more of the antibodies ASCA, I2 and OmpW. Furthermore, five out of the six cases negative for both tTG-ab and EmA showed positivity for the microbial markers. Seroreactivity to ASCA IgA, ASCA IgG and OmpW decreased significantly during gluten-free diet. Conclusions Seroreactivity to different microbial antigens is evident already in patients with early stage celiac disease. ASCA antibodies seem to be gluten-dependent. The results indicate that microbial targets might have a role in the early development of celiac disease.

Background and Aims In nonresponsive celiac disease (NRCD), the symptoms and duodenal damage persist despite a gluten-free diet. Celiac disease patients with persistent symptoms are found to have a dysbiotic microbiota. We thus hypothesized that increased seroreactivity to the serum gluten-sensitive microbial antibodies Saccharomyces cerevisiae (ASCA), Pseudomonas fluorescens-associated sequence (I2), and Bacteroides caccae TonB-linked outer membrane protein (OmpW) is associated with NRCD. Methods ASCA, I2 and OmpW were measured in 20 seronegative CD patients with persistent villous damage despite strict dietary treatment (NRCD group). Fifty-eight responsive patients served as CD controls (55 on gluten-free treatment) and 80 blood donors as non-CD controls. Results At least one microbial marker was positive in 80% of NRCD patients, in 97% of untreated CD and 87% of treated CD patients, and in 44% of controls. NRCD patients had the highest frequency of ASCA positivity (65% vs 52, 20, and 0%, respectively) and also significantly higher ASCA IgA (median 14.5 U/ml) and IgG (32.5 U/ml) titers than treated CD patients (7.0 U/ml, 13.0 U/ml) and non-CD controls (4.5 U/ml, 5.8 U/ml). The frequencies of I2 and OmpW were lower in NRCD than in untreated CD (65% and 45% vs 86% and 59%, respectively), and I2 titers were higher in NRCD (median absorbance 0.76) and untreated (1.0) and treated (0.83) CD than controls (0.32). OmpW was elevated in untreated (1.1) and treated (0.94) CD patients compared with controls (0.79). Conclusions Seropositivity and high titers of ASCA are associated with NRCD and might serve as an additional follow-up tool in CD.