IL-1β-511 and IL-1RN*2 polymorphisms in inflammatory bowel disease: An Italian population study and meta-analysis of European studies

BackgroundSeveral studies have tried to find possible associations between genetic polymorphisms and inflammatory bowel disease prevalence and/or phenotype. Our objectives were to test the frequency and phenotypic association of two polymorphisms of the interleukin-1 pathway, IL-1β-511 and IL-1RN*2, in inflammatory bowel disease patients and controls from an Italian population, and to compare our data with previously published similar studies in Europe.MethodsWe screened 290 inflammatory bowel disease patients (178 ulcerative colitis and 112 Crohn's disease) and 106 controls for IL-1β-511 and IL-1RN*2 polymorphisms by polymerase chain reaction (PCR)-based methods. The prevalence of the IL-1β-511 and IL-1RN*2 polymorphisms in European inflammatory bowel disease patients was calculated by a meta-analysis of previously published studies using the Mantel–Haenszel method.ResultsNo correlation between the IL-1 polymorphisms and inflammatory bowel disease prevalence was found in our study population. Crohn's disease patients with the IL-1β-511 mutation had a higher rate of complicated disease. A trend for an association between the IL-1RN*2 mutation and a higher risk for inflammatory bowel disease has been found only in studies with Northern European populations.ConclusionsThe IL-1β-511 mutation can be associated with complex disease behaviour in Italian Crohn's disease patients. The IL-1RN*2 mutation may play a role in Northern European people with inflammatory bowel disease.