Functional analysis of natural killer cells in children with macrophage activation syndrome / 中华微生物学和免疫学杂志

ABSTRACT

Objective To analyze the functional alteration of natural killer (NK) cells from patients with macrophage activation syndrome (MAS) in active phase and after treatment.Methods Peripheral blood samples were collected from 12 healthy subjects,12 patients with systemic onset juvenile rheumatoid arthritis (SoJIA) but without an episode of MAS and 12 patients with MAS.Flow cytometry analysis was performed to detect NK cells and their expression of perforin,granzyme B,interferon (IFN)-γand tumour necrosis factor (TNF)-α.The cytotoxicity of NK cells to K562 cell was also analyzed.All of the patients with MAS were diagnozed by clinical features and the pathologic examination of hemophagocytosis in bone marrow.The function of NK cells were analyzed before any treatment and on the fifth day as well as in third month after treatment with glucocorticoid,intravenous immunoglobulin and/or cyclosporin A.Results Compared with healthy subjects and patients with SoJIA,patients with MAS had lower NK cell counts,reduced cytotoxicity and decreased expression of perforin and granzyme B before or on the fifth day after treatment (P＜0.05).However,increased production of IFN-γ and TNF-α by NK cells were observed (P＜ 0.05).In the third month after treatment,the cytotoxicity of NK cells and the expression of perforin and granzyme B in patients with MAS were lower than those in healthy subjects and patients with SoJIA (P＜ 0.05),but no statistically significant differences with NK cell counts and production of IFN-γand TNF-α were observed beween the patients with MAS and healthy subjects (P＞0.05).Conclusion NK cells from patients with active MAS were characterized by reduced cytotoxicity and enhanced production of IFN-γ and TNF-α.Upon medical treatment,the number of NK cells in patients with MAS were up-regulated and their production of IFN-γand TNF-α were down-regulated.However,the cytotoxicity of NK cells and the expression of perforin and granzyme B were not affected.Reduced cytotoxicity and decreased production of perforin and granzyme B with NK cells might be the durative features for the patients with MAS.