Two recently published studies are reporting results related to parasitic worms, called helminths, and their possible implications for treating multiple sclerosis. Further study, including the second phase of the reported clinical trial supported by the National MS Society, should determine whether a “probiotic” treatment approach using relatively harmless parasitic worms to alter immune activity will benefit people with MS.
Background: Scientists have noted that autoimmune diseases and allergies are less common in underdeveloped regions. Some researchers have noted that early exposure to common infectious agents – such as that which occurs to people in regions with poor sanitation – may stimulate immune regulation in a positive way and aid healthy immune responses. Because MS is more prevalent in regions with high standards of hygiene, researchers have been testing the “hygiene hypothesis” – the idea that lack of exposure to common innocuous agents at an early age may cause the immune system to over-react and trigger MS.
Studies in MS-like disease in lab rodents and preliminary clinical trials in Crohn’s disease, an autoimmune disease of the bowel, suggest that drinking a concoction containing eggs from parasitic worms might alter immune attacks and improve these conditions.
Wisconsin Study: In the first phase of a clinical trial supported by the National MS Society, John Fleming, MD, and colleagues (University of Wisconsin, Madison) administered a drink containing harmless helminth eggs to five people with MS over three months to determine the safety and preliminary impact of the treatment in relapsing-remitting MS.
The eggs hatch and mature inside the body, reaching about the size of an eyelash. When they reach the large intestine, the larvae interact with the immune system and are then killed. MRI scans were taken by a radiologist who was blinded to the treatments taken to determine increases in MS disease activity.
The results – which compared data before and after treatment – showed that the egg solution was tolerated well. (Multiple Sclerosis 2011 Mar 3. [Epub ahead of print]) Three out of the five participants had mild gastrointestinal symptoms 30 days after the first dose. These symptoms resolved spontaneously within six days. No worsening in neurological symptoms occurred. The number of participants and study design make it difficult to draw firm conclusions about the treatment’s effectiveness, but beneficial trends were noted in relation to MRI and immune activity. Immunologic analyses indicate that a vigorous immune response was mounted in response to the treatment.
The authors note, “Only follow-up studies of longer duration and with larger numbers of subjects will adequately determine safety and efficacy…We strongly discourage administration of this or other helminth preparations outside of clinical trials.”
A second, follow-up study is underway. Dr. Fleming’s team is recruiting 20 patients at two Wisconsin sites (University of Wisconsin, Madison; Marshfield Clinic). Participants are drinking the egg solution every two weeks for 10 months, and are undergoing MRI scans to determine the effects on MS disease activity. If you live near these sites, have relapsing-remitting MS and are interested in this study, read more.
Argentina Study: Jorge Correale, MD, and Mauricio Farez, MD (Institute for Neurological Research, Buenos Aires) observed 12 people with MS and parasitic infections as a follow up to a study they reported in 2007. In the previous study, they reported observations of 12 people with MS and parasitic infections, and they compared clinical, MRI, and immunologic data with 12 uninfected people with MS. Over four years of observation, the infected individuals showed signs of benefit including lower number of relapses, minimal changes in disability scores, and significantly lower MRI activity compared with uninfected people. (Annals of Neurology 2007;61(2):97-108)
In the new, recently published follow-up study (Journal of Neuroimmunology 2011 Jan 28. [Epub ahead of print]),
Drs. Correale and Farez report on further observations of the 12 infected people with MS, compared with 12 uninfected individuals with MS, and 12 controls without MS. After 5.25 years, four of the infected individuals experienced a worsening of infection-related symptoms, and required anti-parasitic treatment. After treatment, MS symptoms and disease-related MRI activity increased to that which was observed in the uninfected people with MS, and blood work showed signs of increased inflammatory immune activity.
The authors note the limitations of this study, in that it included only a small number of people, and no blinding; all participants and clinicians knew who was infected and who was not. (Studies generally use blinding to avoid potential bias.)
Comment: Further research, which is now ongoing, should help shed light on the potential of this probiotic approach for treating MS.
Read more about how National MS Society funding supports the search for MS triggers.