Cytokines in canine inflammatory bowel disease

Abstract Canine inflammatory bowel disease is a group of chronic enteropathies characterized by persistent or recurring gastric symptoms with an unknown etiology which are related to histopathological changes in the mucosa of the small and large bowel in the form of cellular infiltration in the mucosal lamina propria. Recent years have witnessed a growing number of investigations into the role of the immune system and, in particular, cytokines in the development of IBD. In this article, the expression of pro-inflammatory (IL-1, IL-2, IL-5, IL-6, IL-12, IL-18, IFN-γ, TNF-α) and anti-inflammatory cytokines (IL-4, IL-10) was compared in canine patients with IBD based on clinical presentation, breed, lamina propria cell infiltrate and histopathological grade. Only selected studies confirmed higher mRNA expression levels of cytokines IL-2, IL-4, IL-5, IL-12p40, IFN-γ, TNF-α and TGF-β in dogs with IBD in comparison with healthy subjects. GSD were strongly represented in most study populations. Dogs with LPE were characterized by elevated levels of IL-1α, IL-1β, IL-2, IL-5, IL-6, IL-12, TNF-α, TGF-β. The present studies of canine patients with LPC revealed the mRNA expression of cytokines IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p35, IL-12p40, IFN-γ, TNF-α, TGF-β. In the reviewed studies, the progression of IBD was not accompanied by changes in the mRNA expression of IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-18, TNF-α, IFN-γ or TGF-β.