Serum Anti-enteric Neuronal Antibodies And Its Clinical Significance In Patients With Irritable Bowel Syndrome

Background Irritable bowel syndrome (IBS) is one of the most common fuctionalgut diseases which mechanism and pathogenesis remain nuclear now. However, recentstudies had found that anti-enteric neuronal antibodies(AENA) existed in the serum ofIBS patients. The positive rate of AENA in IBS patients was significantly higherthan in non-IBS patients or in healthy controls.Objective To detect the positive rate of AENA and to analyze the relationshipbetween the AENA and clinical symptoms in IBS patients, and then to explore thepossible value of the AENA in the pathogenesis and diagnosis of IBS.Materials and Methods The139IBS patients met the Rome III criteria and the86healthy controls were enrolled in this study. Their serum samples were centrifugedand restored. Indirect immunofluorescence(IIF) was used to detect the AENA withthe substrate of enteric submucosal plexus of guinea pig, and the characteristics of theimmune response were analyzed with doube-blined method. The difference of clinicalsymptoms between the AENA-positive patients and AENA-negative patients wereinvestigated.Results The serum positive reactions of AENA were showed in118(84.9%) IBSpatients, comparing with7.0%in the control group(P=0.000). According to theintensity of the positive immune reactions (IRs), strong positive IRs(+++) were seenin31cases (26.3%), positive IRs (++) in61cases (51.7%), and weakly positive IRs(+)in26patients (22.0%). Of the118IRs in IBS group,81cases showed purelycytoplasm staining,30cases showed cytoplasm and nuclear membrane stainingsimultaneously，3cases cytoplasm and nucleus staining simultaneously,2cases purelynuclear staining, and2cases purely nuclear membrane staining. The all6serumsamples from healthy control showed only cytoplasm staining.The AENA negative IBS patients and the positive patients had no significant differences in age, gender and disease duration. Some abdominal symptoms in IBSpatients with higher AENA titers were more serious than in the patients with negativeor weakly positive antibodies,such as the usually frequent abdominal pain(P=0.048),severe abdominal pain/abdominal discomfort before defecation(P=0.043), higherintestinal symptoms scores (P=0.028), and the significant defecation sense ofurgency(P=0.002). However, the other gastrointestinal symptoms(including theincidence and degree of abdominal pain/discomfort in the “silent status”--nodefecation，the incidence and frequency of abdominal pain/discomfort beforedefecation，the stool change and abdominal pain/discomfort improvement afterdefecation，the sense of anorectal blockage) were not statistically different betweenthe AENA positive group and negative group.Conclusions About84.9%IBS patients have AENA. Some abdominal symptomsin IBS patients with higher AENA titers were more serious than in the patients withnegative or negative and weakly positive antibodies，suggesting that the AENA mayplay a role in the pathogenesis of IBS and may be a potentially valuable biomarker fordiagnosis of IBS.