Increased antibody response to microbial antigens in patients with Crohn's disease and their unaffected first-degree relatives

BackgroundAntibodies directed towards bacterial antigens are considered as serological markers of Crohn's disease. Their role in disease pathogenesis is still under investigation.AimAssess the serologic response towards microbial antigens in Crohn's disease patients, their unaffected first-degree relatives and healthy controls.MethodsThis retrospective study included 60 Crohn's disease patients, 86 unaffected first-degree relatives and 100 healthy controls. Their sera were tested for anti-chitobioside, anti-laminaribioside, anti-mannobioside, anti-Saccharomyces cerevisiae and anti-outer membrane porin C of Escherichia coli.ResultsThe prevalence of anti-chitobioside and anti-laminaribioside was higher in Crohn's disease patients and their first-degree relatives than in healthy controls (51.67%, 61.63% and 8%, respectively, for anti-chitobioside and 76.17%, 88.37% and 23.00% for anti-laminaribioside; p < 0.0001).The cumulative semiquantitative immune response against all the tested antibodies was higher in unaffected relatives than in healthy controls (p < 0.001).The quantitative analysis revealed that serum levels of anti-chitobioside, anti-laminaribioside and anti-mannobioside were similar in first-degree relatives and Crohn's disease patients and higher than healthy controls (p < 0.001).ConclusionsBoth qualitative and quantitative analysis revealed that unaffected first-degree relatives have increased antibody response to microbial antigens. This impaired immunological response towards enteric microorganisms may result from a genetic predisposition.