DEPRESSED NATURAL-KILLER-CELL ACTIVITY IN SCHIZOPHRENIC-PATIENTS

Factors that suppress natural killer (NK) cell activity were examined, in a random sample of 73 schizophrenic patients. NK activity in these patients were compared with 25 healthy age, sex and race matched cont rols. The mean percent of NK activity was 21% in the schizophrenic gro up compared with 30% percent in the controls. The difference between t hese two groups was statistically significant. The mean percent of NK activity in the chronic undifferentiated schizophrenic subgroup and sc hizoaffective subgroup were 20% and 22% respectively. The degree of su ppression of NK activity in the chronic undifferentiated subgroup was higher than in the schizoaffective one, but the difference was not sta tistically significant. The two subgroups were comparable regarding ot her immune related variables such as total white cell count, neutrophi ls, lymphocytes, total protein, albumin, globulin, immunoglobulins and stress. The lower impairment of NK activity in the schizoaffective su bgroup may be due to their exposure to lithium which can enhance immun e functions. Factors associated with significant suppression of NK act ivity in schizophrenic patients were physical restraint, number of psy chotropic medications, number of chronic non-psychiatric diagnoses and race. Psychosocial stressors were associated with suppression of NK a ctivity but it was not statistically significant. Our results identify factors associated with reduced NK activity observed in certain schiz ophrenic patients and NK activity in these patients may be the result of interaction between various factors.