The in vivo expression of cytokine genes in humans.

We used in situ hybridization to study the expression of interleukin genes in sarcoidosis and in persistent generalized lymphadenopathy of HIV disease. In both cases, we found a dramatic over-expression of the interferon-gamma (IFN-gamma) gene as compared to that of the interleukin-2 (IL-2) gene. In sarcoidosis, IFN-gamma producing cells are CD4 T cells and are associated with IL-1 beta gene expressing monocytic cells. In HIV lympadenopathy IFN-gamma producing cells are C8 T cells engaged in cytotoxic function, as demonstrated by the concomitant expression of serine esterase B gene. Thus distinct patterns of interleukin production can be defined in vivo in selected immunopathological situations.