T cell responses in coinfection with Onchocerca volvulus and the human immunodeficiency virus type 1

Onchocerca volvulus and the human immunodeficiency virus (HIV) are two immu nocompromising infectious agents of major public health concern in Uganda. To examine the effect of coinfection with O. volvulus and HN on cellular im mune responses, lymphocyte proliferative responses and cytokine production of peripheral blood mononuclear cells (PBMC) from persons infected with O. volvulus with and without HIV type 1 infection were compared. Proliferation of PBMC to PHA and tuberculin (PPD) in coinfection was less (P = 0.08, P < 0.01) than in O. volvulus infection. O. volvulus extract stimulated lympho cyte proliferation in microfilaria-negative and HIV-negative O. volvulus in fection while only an inconspicuous response was observed in microfilaria-n egative coinfection. After stimulation of PBMC with PPD, the production of interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-5-demonstrated in O . volvulus infection-were reduced in coinfection with HIV ( P < 0.01). Whil e both groups failed to produce IFN-gamma in response to O. volvulus extrac t, only O. volvulus infected persons generated pronounced IL-5 and low IL-4 levels (0.01 > P = 0.02). The cellular immune responses in coinfection sug gested an HIV-related lack of specific reactivity to O. volvulus antigen an d impairment of IL-4 and IL-5 production in addition to the lack of IFN-gam ma response on antigenic stimulation.