Article of the month of August by Dr David Burke

The hygiene hypothesis postulates is certain infectious agents, including helminths, can protect against inflammatory diseases including multiple sclerosis (MS). Necator americanus is a hookworm infecting only humans, which can induce a mixed peripheral T-helper cell respons.. This study examined the effect of hookworm treatment on relapsing MS.

Subjects were clinically stable patients, 18-64 years of age, with relapsing remitting MS or secondary progressive MS. The patients were randomized to a placebo or to a treatment group. The treatment group underwent experimental infection with 25 Necator americanus third-stage larvae (L3), by placement on a gauze pad, then applied to the arm. Arrival in the gastrointestinal system was verified by fecal sampling. The placebo group underwent a similar appearing protocol. The patients were assessed clinically with monthly Expanded Disability Status Scale (EDSS) scores through month ten, and Multiple Sclerosis Functioning Composite Scores at baseline and at nine months. Adverse events were recorded at each visit.

Data were available for 66 patients in the treatment group and 34 in the placebo group. At nine months, 87% of the treatment group and 31% of the placebo group had no MRI changes. From baseline to month nine, an increase was noted in the CD4+CD25 high CD127 neg T cell percentage from total CD4+Tcells in the treatment group while a decrease was found in the placebo group (p =0 .01). Relapses of MS occurred in 11.4% of the treatment group and in 27.8% in the placebo group. There were nine adverse events in seven patients, including five in the placebo and two in the treatment group.

Conclusion: This study of patients with relapsing multiple sclerosis found that treatment with a hookworm could decrease the number of MS relapses.

Tanasescu, R et al. Hookworm Treatment for Relapsing Multiple Sclerosis. A Randomized Double-Blind Placebo Controlled Trial. JAMA Neurol. 2020. doi:10.1001/jamaneurol.2020.1118.