The Characteristics Of Peripheral Blood Natural Killer Cells In Patients With Neuromyelitis Optica Spectrum Disorders

Objective:To analyze characteristic of peripheral blood natural killer(NK)cells in neuromyelitis optica spectrum disorders(NMOSD).Explore related factors and significance for NK cells in patients with NMOSD.Methods : We retrospectively analyzed patients totally from November 2014 to August 2018 in Renji Hospital,including 78 NMOSD(42 cases in acute phase,36 cases in remission stage),24 patients of multiple sclerosis(MS),103 patients of acute cerebral infarction(ACI).27 healthy volunteers in our hospital were selected as control group(HC)at the same period.The clinical and biochemical data of patients were collected.One-way ANOVA Dunnett T3 test was used for pairwise comparison of NK cell levels in NMOSD and other disease groups.We detected the expression level of NK cell in peripheral blood in patients with NMOSD and MS through receiver operating characteristic(ROC)analysis.Among the NMOSD group,it was divided into two groups by NK cell level of the disease stage.The independent t-test or Kruskal-Wallis Test was used to compare the clinical characteristics.The association between NK cells and disease onsets/ clinical characteristics was assessed by Pearson or Spearman correlation analysis.The difference was statistically significant when P<0.05.Results: 1.Between the four groups,there were no significant differences in CD19、CD3、CD4、B lymphocytes、T lymphocytes and Ts lymphocytes(p > 0.05),and there were statistically significant differences in CD8 、 CD4/CD8 、 the percentage of NK cells 、 Th lymphocytes、Th/Ts and NK cells(P<0.05).Compared with MS,ACI and HC,the level of NK cells in peripheral blood was lower in NMOSD patients and was moderately correlated with the incidence of NMOSD(r=0.325,p<0.001;r=0.381,p<0.001;r=0.413,p<0.001).According to the hierarchical analysis of ROC curve,the cut-off value of NK cell level used to distinguish patients with NMOSD from MS was 266.850cells/uL,with a sensitivity of 87.18%,a specificity of 54.17%.2.There were 42 cases of NMOSD in acute phase and 36 cases in remission stage.The NK cell level in peripheral blood was 114.10(64.75-153.38)and 167.60(116.35-266.15)in groups with NMOSD acute and remission,respectably(p<0.001).3.In patients of NMOSD,relapse of disease was negatively correlated with NK cells(r=-0.2362,p=0.0474).Acute stage was also negatively correlated with NK cells(r=-0.366,p=0.001).NK cell was not correlated with attack age、gender、recurrence rate、disease duration、EDSS、cervical cord lesions and AQP4-Ab in patients of NMOSD.Conclusion:The results showed that the level of NK cells in NMOSD patients was lower compared with patients of MS、ACI and HC,especially in acute stage,and was correlated with relapse of disease and acute stage.It suggested that NK cells may play a pathogenic role in NMOSD.It may be helpful to explore the immune mechanism of NMOSD.NK cell may participate in the diagnosis and clinical monitoring of NMOSD.