Anti-Saccharomyces cerevisiae and perinuclear anti-neutrophil cytoplasmic antibodies in coeliac disease before and after gluten-free diet

Background: Anti-Saccharomyces cerevisiae and perinuclear anti-neutrophil cytoplasmic autoantibodies are markers of Crohn's disease and ulcerative colitis respectively. Aim: To determine the prevalence of anti-S. cerevisiae and perinuclear anti-neutrophil cytoplasmic autoantibodies in a large series of coeliac disease patients before and after gluten free diet, and to correlate anti-S. cerevisiae-positivity with intestinal mucosal damage. Methods: One hundred and five consecutive coeliac disease patients and 141 controls (22 ulcerative colitis, 24 Crohn's disease, 30 primary sclerosing cholangitis, 15 postenteritis syndrome, 50 blood donors) were tested for anti-S. cerevisiae by enzyme-linked immunosorbent assay and for perinuclear anti-neutrophil cytoplasmic autoantibodies by indirect immunofluorescence. Results: In coeliac disease anti-S. cerevisiae (immunoglobulin G and/or immunoglobulin A) were slightly less frequent (59%) than in Crohn's disease (75%, P = 0.16) and significantly more frequent than in ulcerative colitis (27%), primary sclerosing cholangitis (30%), postenteritis syndrome (26%) and blood donors (4%) (P = 0.009, P = 0.0002, P = 0.025, P < 0.0001). No correlation was found between anti-S. cerevisiae and degree of mucosal damage. Perinuclear anti-neutrophil cytoplasmic autoantibodies were detected only in one coeliac. After gluten free diet the disappearance of anti-S. cerevisiae-immunoglobulin A (93%) was more frequent than that of immunoglobulin G (17%, P = 0.0001); perinuclear anti-neutrophil cytoplasmic autoantibodies disappeared in the only coeliac positive at diagnosis. Conclusion: More than half of untreated coeliacs are anti-S. cerevisiae-positive irrespective of the severity of mucosal damage. Differently from immunoglobulin A, anti-S. cerevisiae-immunoglobulin G persisted in more than 80% after gluten free diet. The high prevalence of anti-S. cerevisiae in coeliac disease suggests that they may be the effect of a non-specific immune response in course of chronic small bowel disease.