Augmentation of selective monocyte functions in tuberculosis

Four monocyte functions were studied in patients with pulmonary tuberculosis and in healthy subjects. Circulating monocytes from four of six patients with tuberculosis functioned as suppressor cells; depletion of adherent cells from mononuclear cells obtained from the peripheral blood of these patients resulted in a 37-fold enhancement in tuberculin purified protein derivative-induced incorporation of [³H]thymidine. Monocytes from patients with tuberculosis exhibited increased adherence to plastic. Plasma from patients with tuberculosis also increased the adherence of monocytes from healthy subjects. However, basal and lipopolysaccharide-stimulated production of prostaglandin E₂ by monocytes and tumoricidal activity were not altered in patients with tuberculosis. Thus, tuberculosis in humans is associated with the enhancement of selective monocyte functions. The dissociation in monocyte effector functions in human mycobacterial infection has potential implications not only for the course of tuberculosis but also for immunoadjuvant therapy.