Dysregulation of cytokine expression in monocytes from HIV-positive individuals

Abstract

Because HIV may alter the production of inflammatory factors produced by monocytes, the expression of tumor necrosis factor alpha (TNF-alpha), tissue factor (TF), interleukin (IL)-1 beta, and IL-6 was evaluated in 47 HIV-seropositive persons and seronegative control subjects. RNA was extracted from freshly isolated lipopolysaccharide (LPS)-stimulated or unstimulated monocytes. Cytokine and TF expression was quantitated by dot blot hybridization or a reverse transcription polymerase chain reaction (RT-PCR). A significant depression of TF mRNA was observed in LPS-stimulated monocytes (66% less in AIDS, 20% less in AIDS-related complex (ARC), and 0% less in asymptomatic patients), whereas normal responses were observed for TNF-alpha, IL-1 beta, and IL-6. When constitutive expression was measured in unstimulated monocytes by RT-PCR, a differential pattern was also observed. TNF-alpha and IL-1 beta were positive in 85% of asymptomatic persons, compared with only 27% of ARC and 42% of AIDS patients. Expression of IL-6 was observed in lower proportions, 27-30%, with no significant differences among disease states. All samples were negative for TF. Thus, the regulation of inflammatory molecules is differentially altered in individuals with HIV infection. TF is preferentially down-regulated, compared with TNF-alpha, IL-1 beta, and IL-6, in LPS-stimulated monocytes as patients progress to AIDS. TNF-alpha and IL-1 beta are preferentially up-regulated, compared with IL-6 and TF, in unstimulated monocytes in asymptomatic persons, with a loss of up-regulation as patients progress to AIDS.