Parasites may reduce relapse in MS patients

Parasitic worms may have their uses after all. The bugs could alter the course of autoimmune diseases like multiple sclerosis (MS), a new study suggestsPrevious studies have suggested that parasites can influence the progression of autoimmune diseases in animals. To test whether this was also the case in humans, Jorge Correale and Mauricio Farez at the Raul Carrea Institute for Neurological Research in Buenos Aires, Argentina, spent four-and-a-half years following the disease progression of 24 people with MS. Half of the patients had recently shown symptoms of parasitic infection, while the remaining 12 were otherwise healthy controls.Every three months the patients were checked for disease activity and any worsening of symptoms, and during the final 18 months of the study their blood was checked for immune cell activity.Those infected with parasites had fewer relapses, and less overall deterioration of their condition than uninfected people with MS. There were just three relapses in the parasite group in total compared with 56 relapses in the uninfected group."This is the first direct evidence that parasites might be relevant to protection from an autoimmune disease," says Graham Rook, an immunologist at University College London, UK, who was not involved in the study.Hygiene hypothesis...