Immunologic mechanisms in multiple sclerosis. Exacerbation by type A hepatitis and skin test antigens.

A 29-year-old man with quiescent multiple sclerosis had hemiparesis during the prodrome of serologically confirmed type A hepatitis. After neurological symptoms and acute hepatitis had abated, hemiparesis again developed when skin tests were applied. While he was receiving prednisone, skin test inflammation and neurological signs cleared. One year later, lymphocyte stimulation, which had been noticeably elevated during his exacerbations, returned to low normal. Both hepatitis A and skin test antigens produced immunostimulation that resulted in exacerbation of multiple sclerosis.