Analysis of the systemic immune response in HIV-1-infected patients suffering from opportunistic Candida infection

Infection by HIV-1 is a major risk factor predisposing for fungal infection. However, few studies have addressed the immunological status of HIV-1 patients suffering fungal infections. This study examines the status of polymorphonuclear phagocytes (PMN) and T cells in HIV-1-infected patients suffering from mucosal Candida infections. These patients had a more immature population of blood PMN, as detected by lower CD18 expression, than HIV asymptomatics or healthy controls. They also had a selective defect in T cell activation in response to phytohemagglutinin (PHA), but not to stimulation through the T cell receptor by anti-CD3 crosslinking, when compared to HIV-1 asymptomatic patients. This was shown by a decrease in cellular proliferation and cell surface expression of CD69, CD25 and CD71 activation antigens. There was also a severe impairment of IL-2 production upon activation by PHA. IL-10, and TNF secretion was also reduced, whereas IFN-gamma and IL-5 production was not affected. No correlation with viral load, CD4 or CD8 T cell number or clinical stage was found. In conclusion, our results indicate that Candida-infected HIV patients have a selective defect, independent of viral load, CD4 or clinical status, involving some aspects of T cell activation, IL-2 production being severely impaired.