ABNORMAL INTRACELLULAR IL-2 AND INTERFERON-GAMMA (IFN-GAMMA) PRODUCTION AS HIV-1-ASSOCIATED MARKERS OF IMMUNE DYSFUNCTION

We used three-colour cytometry to analyse intracellular cytokine produ ction in activated whole blood cultures derived from patients with HIV -1 infection. We assessed mitogen-induced IL-2, IL-4 and IFN-gamma pro duction from T cells as possible markers of immune dysfunction. The pe rcentages of T cells staining for IL-2 were significantly reduced in s timulated cultures from HIV+ individuals relative to normal controls ( P<0.0001); this reduction was observed in both the CD4(+) and the CD8( +) subsets. IL-2 production was significantly reduced in CD4(+) T cell s from HIV+ individuals clinically classified as symptomatics compared with HIV+ asymptomatics (P<0.001); in addition, production of IL-2 in versely correlated with viral load (r(2)=0.832). On the other hand, HI V+ individuals showed significantly more T cells staining positive for IFN-gamma (P < 0.0001) subset analysis identified these T cells as CD 8(+). Increased IFN-gamma production in the CD8(+) T cell subset of HI V+ individuals correlated neither with clinical status nor with plasma viral load. IL-4 staining in activated T cells was low (<5%) and no d ifferences were observed between HIV+ and control groups. Three-colour FAGS analysis of whole blood provides a sensitive, rapid and relative ly easy means to detect cytokine profiles within T cell subpopulations . Only small volumes of blood are required (0.5 ml), since there is no need for cell isolation, making it more practical than ELISA or rever se transcriptase-polymerase chain reaction (RT-PCR) for the analysis o f immune function in HIV+ individuals. This technique could therefore play a role in mapping the dynamics and extent of immune recovery in A IDS patients undergoing triple combination therapy.