Circulating levels of IL-18 in adult and paediatric patients with HIV-1 infection

IL-18, formerly IFN- gamma -inducing factor, is produced by several cell types, including activated mononuclear cells and epidermal cells. Furthermore, IL-18 induces the production of IFN- gamma from natural killer cells, and along with IL-12 has a synergistic effect on the induction of IFN- gamma . Recently, Shapiro et al. suggested a role for IL-18 in HIV-1 pathogenesis because of the ability IL-18 shares with the proinflammatory cytokines IL-1 and TNF to stimulate HIV-1 production in the chronically infected U1 monocytic cell line. To confirm these in-vitro results, and to gain further insight into the role of IL-18, we evaluated circulating levels of IL-18 in adult and paediatric HIV-1-infected patients at various phases of the disease.