IFNG and periodontitis: In this paper we investigated the cell surface receptor expression, activation markers, cytokine secretion and cell death profiles of mononuclear cells obtained from peripheral blood, oral blood and gingival tissues of healthy individuals and patients with periodontitis when they were left untreated or treated with interleukin 2 (IL-2), interferon-gamma (IFN-γ) and phorbol myristate acetate (PMA)/ionomycin (I).