FLOW-CYTOMETRIC ASSESSMENT OF IN-VIVO CYTOKINE-PRODUCING MONOCYTES INHIV-INFECTED PATIENTS

We have used two-color flow cytometry to study in vivo monocytic cytok ine production at the single-cell level in HIV-infected patients. We d emonstrated the presence of intracellular IL-1 alpha, IL-1 beta, IL-1r a, and TNF alpha in circulating CD14(+) monocytes from HIV-infected pa tients, The specificity of intracellular staining with anti-cytokine a ntibodies was demonstrated by the suppression of the fluorescent signa l when staining was performed in the presence of recombinant cytokines . We did not detect any specific intracellular staining when anti-IL-4 antibodies were used since monocytes do not produce IL-4. In vivo int racellular cytokine production of IL-1 alpha, IL-1 beta, IL-1ra, and T NF alpha was higher in monocytes from HIV-infected individuals compare d to monocytes from healthy controls; however, only the data concernin g IL-1 alpha reached statistical significance. Monocytic cytokines are involved in the regulation of HIV gene expression and may participate in the modulation of the Th1/Th2 balance. The ability to follow the p roduction of a wide range of cytokines by circulating monocytes of HIV -infected patients should allow one to better analyze the role of mono cytic cytokines in the pathogenesis of HIV disease. (C) 1997 Academic Press.