Immunocytochemical characterization of the macrophage and lymphocyte infiltrate in the brain in six cases of human encephalitis of varied aetiology.

Monoclonal antibodies that react with various macrophage and lymphocyte sub-populations have been applied to acetone-fixed cryostat sections of brains from six cases of human meningo-encephalitis (two cases of subacute sclerosing panencephalitis, two cases of allergic encephalitis, one case of suspected entero-virus meningo-encephalitis and one case of meningo-encephalitis of undetermined origin). The patterns of inflammatory cell response that these antibodies reveal is described and discussed in comparison with published descriptions of the corresponding cell types found in the brain in Japanese encephalitis, herpes simplex encephalitis and multiple sclerosis. In general, in the acute phases of inflammatory central nervous system diseases, T lymphocytes and macrophages predominate in the parenchyma, while the early phases of a B cell response take place in perivascular spaces.