Defective natural killer cell activity and deficient production of interferon-γ in children with acute lymphoblastic leukemia

Natural killer (NK) cell activity, OK-432-augmented-NK cell activity, concentrations of interferon-γ (IFN-γ) in the culture supernatants of lymphocytes stimulated with OK-432, and subsets of NK cells and memory T cells were analyzed in 42 children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy. Natural killer and augmented-NK cell activities, and concentrations of IFN-γ in the supernatants of cultured lymphocytes, were significantly lower in the patients with ALL than in age-matched control children. Among the NK cell subsets, proportions of CD57⁺ cells in the patients with ALL were significantly higher than in the controls, and proportions of a memory T cell subset (CD4⁺ CD29⁺ T cells) in the patients were also significantly higher than in the controls. These results suggest that the function of NK cells and memory T cells that are considered as IFN-γ producing cells, may be defective in ALL, and that CD57⁺ cells and CD4⁺ CD29⁺ cells may be resistant to or recover rapidly from suppression by cytotoxic chemotherapy.