The mitogen induced lymphocyte responses were measured in 33 depressed patients categorized according to the DSM-III into minor (300.40, 309.00), simple major (296.X2) and major depression with melancholia and/or psychotic features (296.X3, 296.X4). Three distinct mitogens were used, i.e. phytohemaglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A (CON A). We found that major depressives with associated features showed significantly lower mitogen induced lymphocyte responses to PHA and PWM as compared to all other depressed patients. The severity of illness was significantly inversely related to the lymphocyte responses to PHA. Cortisol nonsuppressors exhibited significantly lower PHA and PWM induced lymphocyte responses as compared with suppressors. There were significant and negative correlations between the postdexamethasone Cortisol values and the PHA and PWM stimulated lymphocyte responses.
