[The impairments of natural killer cell activity and interferon response in advanced malignant disease]

Abstract

Natural killer (NK) cells are a distinct subpopulation of lymphocytes with specific functional and phenotypic features, responsible for non-major histocompatibility complex (MHC) and restricted cytotoxic function without previous sensitization. The control of primary tumor growth and its hematogenous spreading is one of the most important functions of NK cells. Defect of NK cell activity present in malignancy correlates with clinical stage and progression of the disease. In patients with localized or undisseminated malignancies NK cell activity can be normal or even enhanced, while in most of the patients with widely disseminated tumors base-line NK cell function is markedly impaired. In patients with advanced malignant disease NK cell response to interferon (IFN) is impaired, without abnormalities of IFN production. The reason could be the inactivation of stimulators already present in plasma or direct toxic impairment of NK cells, either during the maturation of NK cell progenitors or/and during the activation of the existing NK cell effectors.