Psoriasis and inflammatory bowel diseases

Psoriasis and inflammatory bowel diseases (Crohn's disease and ulcerative colitis) are among the immune-mediated inflammatory diseases. This group includes approximately 80 disorders, some of which can at times be associated in a single patient. In psoriasis, Crohn's disease may be observed slightly more frequently, but ulcerative colitis and celiac disease are also an issue. The underlying relations between these disorders comprise: i) genetic data obtained by genome-wide association studies that show the involvement of shared predisposing loci and/or genes, for example, in innate immunity ; ii) immunological data : these disorders share inflammation effector mechanisms, particularly the activation pathway of Th17 lymphocytes, which explains the efficacy of anti-TNF antibodies and anti-IL-12/23 ; and iii) environmental co-factors such as smoking, possibly certain food proteins (gliadin, etc.), and bacterial infections that are probably decisive elements in the genesis of these diseases. (c) 2012 Elsevier Masson SAS. All rights reserved.