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BioMed Research International
Volume 2013 (2013), Article ID 983902, 8 pages
http://dx.doi.org/10.1155/2013/983902
Review Article

Correlations between Psoriasis and Inflammatory Bowel Diseases

Department of Dermatology “Daniele Innocenzi”, A. Fiorini Hospital, Sapienza University of Rome, Via Firenze, Polo Pontino, 04019 Terracina, Italy

Received 17 April 2013; Accepted 27 June 2013

Academic Editor: Oliver Stoeltzing

Copyright © 2013 Nevena Skroza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

For a long time the relationship between inflammatory bowel diseases (IBDs) and psoriasis has been investigated by epidemiological studies. It is only starting from the 1990s that genetic and immunological aspects have been focused on. Psoriasis and IBD are strictly related inflammatory diseases. Skin and bowel represent, at the same time, barrier and connection between the inner and the outer sides of the body. The most important genetic correlations involve the chromosomal loci 6p22, 16q, 1p31, and 5q33 which map several genes involved in innate and adaptive immunity. The genetic background represents the substrate to the common immune processes involved in psoriasis and IBD. In the past, psoriasis and IBD were considered Th1-related disorders. Nowadays the role of new T cells populations has been highlighted. A key role is played by Th17 and T-regs cells as by the balance between these two cells types. New cytokines and T cells populations, as IL-17A, IL-22, and Th22 cells, could play an important pathogenetic role in psoriasis and IBD. The therapeutic overlaps further support the hypothesis of a common pathogenesis.