皮肌炎患者NK细胞衰老介导其"高炎性反应-弱抗感染"的矛盾表型OA

Objective To explore the intrinsic mechanism of the contradictory phenotype"high inflammation and weak anti-infection"in MDA5 antibody-positive in patients with dermatomyositis(MDA5+DM),and to clarify the senescent characteristics and functional status of peripheral blood natural killer(NK)cells,thus provide experi-mental basis for developing new DM therapeutic strategy.Methods Single-cell RNA sequencing(scRNA-seq)was used to analyze the Senescence-Associated Secretory Phenotype(SASP)score and function-related differential genes of peripheral blood NK cells in 6 MDA5+DM patients and 2 healthy controls(HC).Peripheral blood was collected from 83 patients(38 in active phase,45 in stable phase)and 44 HCs.C12FDG staining combined with flow cytome-try was performed to detect the senescent phenotype of NK cells.The secretion level of interferon-γ(IFN-γ)and granzyme B(GZMB)in NK cells were measured under basal conditions and after IL-12/IL-15/IL-18 stimulation.Spearman correlation analysis was applied to evaluate the association between NK cell senescence degree and function.Results ScRNA-seq showed that the SASP score of NK cells in DM patients was significantly higher than that in HC(P＜0.001).The mean fluorescence intensity(MFI)of C12FDG in peripheral blood NK cells of DM pa-tients in both active and stable phases was significantly higher than that in HCs(P＜0.05 and P＜0.001,respective-ly),with no significant difference between different disease stages.Functional tests revealed that the basal secretion level of IFN-γ and GZMB in DM patients'NK cells were significantly higher than those in HCs(P＜0.01 or P＜0.0001).Incubation with IL-12/IL-15/IL-18,reduced IFN-γ secretion level and inhibited its increase in DM patients'NK cells as compared to the situation in HCs(P＜0.05 or P＜0.000 1),while GZMB secretion remained at a high level,and like HCs,it showed almost no response to cytokines.Correlation analysis suggested a moderate negative correlation between NK cell C12FDG accumulation and IFN-γ stress response ability(r=-0.398 1,P=0.002 9).Conclusions dPeripheral blood NKf cells in DM patients show obvious senescent characteristics,which are closely related to the de-fective stress response of IFN-γ secretion.This may contribute to the formation of the"high inflammation and weak anti-infection"contradictory phenotype in DM patients.This result provides experimental basis for developing therapeutic strategies targeting at NK cell senescence and for identification of related biomarkers in DM patients.