Sequential studies of lymphocyte responsiveness and antibody formation in acute bacterial meningitis.

Lymphocyte transformation responses in vitro were studied in eight patients with acute bacterial meningitis (in five due to Neisseria meningitidis). Sequential studies were done from 24--48 hr after the first symptoms of infection to complete recovery. In all cases lymphocyte transformation was depressed during the acute phases of illness. The responses to microbial antigens were more affected than the responses to mitogens. The course of the lymphocyte responses to the causative micro-organism showed no difference from the responses to other microbial species. A moderate shift towards increased sensitivity of the lymphocytes to lower doses of the causative micro-organism was observed during the course of illness in three cases. In N. meningitidis infection, a rapid rise was seen in the serum titres of complement-fixing antibodies and in the number of precipitating antibodies, whereas the rise in immunoglobulin concentrations was more prolonged. Characteristic patterns of elevation and return towards normal were found in the serum concentrations of the acute-phase reactants alpha1-antitrypsin, haptoglobin, and orosomucoid. It is concluded that the lymphocyte transformation responses in vitro during severe bacterial infection are largely governed by non-specific factors, and that studies of lymphocyte responses to micro-organisms should always include other microbial species as controls.