SPECIFIC CELLULAR IMMUNE UNRESPONSIVENESS IN HUMAN FILARIASIS

Abstract

In an effort to identify factors important in the pathogenesis of filarial disease, studies of the cellular and humoral immune responses to the parasitic nematode Wuchereria bancrofti were carried out on 39 individuals in a region of the Pacific where filariasis in endemic [Polynesia]. Blood lymphocytes from 26 patients with chronic filariasis (especially that associated with persistent microfilaremia) gave only minimal responses to filarial antigens when challenged in vitro in a lymphocyte transformation assay. Brisk responses to these same antigens were elicited in cultures of cells from a control population of 13 exposed but not infected individuals living in the same area, the greatest responses being found in uninfected children less than 10 yr old. The poor cellular reslonsiveness of infected individuals was filaria antigen-specific, as reactivity to tuberculin (PPD purified protein derivative) and streptococcal (SK-SD [streptokinase-streptodornase]) antigens was normal and equal in all groups. The immunologic deficit was limited to cell-mediated immune responses and appeared unchanged 2 wk after treatment of the patients with the anti-filarial drug diethylcarbamazine. There apparently is a state of antigen-specific cellular unresponsiveness in patients with this chronic parasitic infection. This immunologic deficit may be of fundamental importance in the pathogenesis of filarial disease.