Atividade natural Killer em pacientes com depressão maior

Abstract

Major Depression (MD) poses a great public health problem, where the prevalence in the male adult population varies from 2% to 3%, reaching values 2-3 times as high in females. The association between MD and altered Natural Killer (NK) activity has been repeatedly suggested, but experimental data show contradictory results. NK activity assays were performed in patients with DM, unipolar subtype, and healthy subjects. The NK activity was assayed in a standard 4-hour Cr release assay, using as target the K562 human erythroleukemia­derived cell line. Patients were free from medical disorders clearly associated with immunity disorders such as ongoing infections, cancer, immunodeficiencies and autoimmune disease. The psychiatric diagnoses were made using the DSM-III-R Checklist (kappa = 0,875 for the evaluator). We also measured nutritional parameters (ferritin, folie acid, vitamin B12, transferrin, albumin, hemoglobin, and index of body mass) and integrity of the adrenal axis (cortisol). A rigorous pairing was employed (gender, age, race, socio-economical leveis, tobacco, contraceptive use, menses and physical activity), to exclude externai factors influencing natural immunity. NK activity was significantly lower in patients as compared to healthy controls (p = 0,001)A relationship between NK activity and measure of hypothalamic-pituitary-axis function, such as baseline cortisol secretion, was not found in patients. No significant changes were observed in the index of body mass and others nutritional variables. Patients with familiai history of mental disease presented lower NK activity (p = 0,03). This finding may suggest that the sarne genetic factors are presumably associated to the etiology of depression and NK activity changes.