Japanese encephalitis: identification of inflammatory cells in cerebrospinal fluid.

Fifteen patients with acute encephalitis were studied during the epidemic season of Japanese encephalitis (JE) in Northern Thailand; 13 of 15 proved to have the encephalitis. In serial cerebrospinal fluids and blood samples, mononuclear cells were identified using monoclonal antibodies. In cerebrospinal fluid from the patients with Japanese encephalitis, T cells predominated with a 4.2:1 ratio of T helper/inducer cells to T suppressor/cytotoxic cells; B cells and macrophages were often present but in small numbers compared to their presence in blood. Distribution of cell types did not vary between the first and fifth day of hospitalization, were similar in fatal and nonfatal cases, and were unaffected by administration of steroids.