Helminth therapy and multiple sclerosis.

Multiple sclerosis is a common and frequently disabling neurological disease of young adults. It is characterised by recurrent areas of focal inflammation (plaques) in the CNS which give rise to episodic neurological signs and symptoms. According to the hygiene (microbial deprivation) hypothesis, evolutionarily abnormal high levels of sanitation in the environment of the developed world may contribute to disordered immunoregulation in this and other putative autoimmune disorders. Helminths have been shown to augment immunoregulation. On this basis, the possibility of treating multiple sclerosis with live helminths or helminth products has been explored in animal models, natural human infections and phase 1 clinical trials. To date helminth therapy appears safe and preliminary clinical, magnetic resonance imaging and immunological outcomes have generally been favourable. Nevertheless, serious adverse effects are always possible, particularly with live parasitic administration. Follow up studies with safety monitoring, regulatory oversight and objective outcome measures will be required to definitively assess safety and efficacy for this novel class of potential immunological therapies in multiple sclerosis.