Can the study of helminths be fruitful for human diseases?

Abstract

Parasitic helminths have an inclination to be long-lived invaders with certain human parasites reported as surviving for in excess of a decade. Such longevity tends to be associated with an apparent lack of pathology and one contributor to this perhaps somewhat surprising situation is likely to be the secretion of anti-inflammatory immunomodulators by the worms. Such molecules act to dampen and effect the polarization of immune responses and this invariably potent immunomodulation frequently extends to responses to third party antigens, vaccines and other diseases. Relating to the latter, a particularly serendipitous consequence of worm infection that is being increasingly recognized, is its effect on human conditions that are associated with aberrant inflammation. For this reason, helminths have within the last decade attracted substantial attention in the research community as a potential source of novel therapies against allergic and autoimmune diseases. In this article we describe the effects of helminths on five such diseases-asthma, rheumatoid arthritis, multiple sclerosis, type I diabetes and inflammatory bowel disease. In particular, we consider the immunological mechanisms that underlie helminth-mediated protection against these diseases and in addition, highlight individual helminth molecules that may have therapeutic potential.