HIV-positive men differ in immunologic but not catecholamine response to an acute psychological stressor

Acute psychological stress in humans induces sudden alterations in catecholamine plasma levels and in the distribution of peripheral blood lymphocytes. The purpose of this study was to investigate whether infection with the human immunodeficiency virus (HIV) had an impact on the psychoneuroimmunologic axis. Twelve asymptomatic HIV-positive homo- or bisexual men (CD4 cell counts>400/mm3) and 13 healthy HIV-negative control subjects were exposed to an acute psychological stressor consisting of a 30 min semi-structured stress interview using emotion- and client-centered conversation techniques surrounded by two relaxation periods. Changes in neuroendocrine and immunological, as well as cardiovascular parameters, were intermittently monitored. Under the influence of the stressor plasma norepinephrine (NE) levels increased significantly in HIV-positive patients (+30.6%; p<0.05) and in HIV-negative individuals (+17.5%; n.s.). These changes were paralleled by significant increases in blood pressure and heart rate. Plasma cortisol decreased continuously from initially high levels during the entire experimental setting in both groups, compatible with an adaption reaction. Concomitantly, WBC and neutrophilic granulocytes increased significantly in HIV-negative subjects, while they were blunted in HIV-positive patients. Interestingly, NK cell increases were significantly higher during the stress experiment in HIV-positive patients than in HIV-negative controls. CD4+ and B cell counts remained unaffected by the stressor. These results suggest that catecholamine secretion induced by an acute psychological stressor is preserved in HIV-infected patients with the responsiveness of WBC and neutrophilic granulocytes being diminished, while NK cells showed an increased response.