Intrauterine administration of human chorionic gonadotropin (hCG) activated peripheral blood mononuclear cells (PBMC) has positive effect on embryo implantation in repeated implantation failure patients. This effect is mainly caused by the PBMC cytokine production. The aim of this study was to find association between the tumor necrosis factor alpha (TNFα), interleukin 6 (IL6), interleukin 4 (IL4) and interleukin 10 (IL10) plasma levels and their respective concentrations in the media of cultivated PBMC alone or treated with hCG.