Increased spontaneous secretion of interleukin 6 and tumor necrosis factor alpha by peripheral blood lymphocytes of human immunodeficiency virus-infected children

Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) have been implicated in the transition of nonreplicating latent human immunodeficiency virus (HIV) infection to the replicating state of productive infection. In HIV infection increased concentrations of these cytokines in serum have also been found in association with hypergammaglobulinemia. We have analyzed the ability of peripheral blood mononuclear cells (PBMC) of HIV-infected children to secrete IL-6 and TNF-alpha. In kinetic studies, optimum spontaneous IL-6 secretion by 1 x 10⁶ PBMC was achieved at 24 hours. The mean spontaneous IL- 6 and TNF-alpha concentrations secreted by PBMC of known HIV-infected children (age range, 8 months to 11 years) were 1686 and 131 pg/ml, respectively, compared with 56 and 45 pg/ml, respectively, in normal healthy controls. No significant correlation was observed between spontaneously secreted IL-6 and TNF-alpha in culture supernatants with CD4 or CD8 numbers; with serum IgG, IgA and IgM concentrations; or with lymphoproliferative responses to recall antigens. There was, however, an association between ability to secrete IL-6 with HIV-specific in vitro antibody production. Spontaneous IL-6 secretion decreased transiently after initiation of antiretroviral therapy, returning to original values with continued treatment. Cytokine derangement in HIV-infected children includes PBMC- derived spontaneous IL-6 and TNF-alpha secretion.