Suppression of inflammation by helminths: a role for the gut microbiota?

Abstract

Multiple recent investigations have highlighted the promise of helminth-based therapies for the treatment of inflammatory disorders of the intestinal tract of humans, including inflammatory bowel disease and coeliac disease. However, the mechanisms by which helminths regulate immune responses, leading to the amelioration of symptoms of chronic inflammation are unknown. Given the pivotal roles of the intestinal microbiota in the pathogenesis of these disorders, it has been hypothesized that helminth-induced modifications of the gut commensal flora may be responsible for the therapeutic properties of gastrointestinal parasites. In this article, we review recent progress in the elucidation of host-parasite-microbiota interactions in both animal models of chronic inflammation and humans, and provide a working hypothesis of the role of the gut microbiota in helminth-induced suppression of inflammation.

Keywords: helminth-induced suppression of inflammation; hookworms; host–parasite interactions; microbial richness; microbiota; whipworms.

Figure 1.

Potential role for microbiota in helminth-mediated suppression of autoimmune diseases? Helminths, including Trichuris sp. and hookworms are thought to limit the severity of IBDs and autoimmune diseases via promotion of type 2 and regulatory T cell responses that counteract pro-inflammatory type 1 or type 17 immune responses. However, emerging evidence suggests that helminth-mediated immune modulation may be, in part, due to alterations in the composition of the intestinal microbiota, which can profoundly influence immune cell development and function in the intestine. ES, excretory/secretory. (Online version in colour.)