Abstract
The sera of 176 MS patients and of 150 healthy adult controls were assayed for antibodies against mumps, rubella, Sendai and herpes simplex viruses, a higher prevalence of measles c.f.a. having already been demonstrated in the MS patients. The CSF of 48 of the MS patients were subjected to the same tests. The patients differed from the controls in a higher prevalence of h.i.a. to mumps and of c.f.a. to herpes simplex. For the latter, but not for the former, the prevalence was statistically higher only in patients treated with immunosuppressants. To date measles seems to be the most seriously incriminated virus in the etiopathogenesis of MS, mumps ranking second.