Intravenous immunoglobulin prevents release of proinflammatory cytokines in human monocytic cells stimulated with procalcitonin

The aim of this study was to investigate whether the stimulation of monocytic cells with procalcitonin (PCT) results in the release of proinflammatory cytokines. The effects of intravenous immunoglobulin (IVIG) on the production of cytokines from the cells stimulated with PCT were also studied. Cultured monocytic cells [THP-1 cells treated with phorbol myristate acetate or peripheral blood mononuclear cells (PBMCs)] were stimulated with PCT. The protein levels of proinflammatory cytokines [tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-6 and high mobility group box-1] in the culture supernatants were determined by ELISA kits. The concentration of PCT-specific IgG antibody in IVIG was measured using a specific ELISA. PCT induced the release of cytokines from THP-1 cells in a time- and dose-dependent manner. IVIG inhibited the release of cytokines from the cells stimulated with PCT. It was confirmed that IVIG also inhibited TNF-alpha release in the same dose range for PBMCs stimulated with PCT. The presence of PCT-specific IgG antibody was detected in the tested IVIG, which might be one of the mechanisms. PCT induced the release of proinflammatory cytokines from THP-1 cells and PBMCs. The function of PCT was prevented by the presence of IVIG.