Study On The Correlation Between IFN-α And NK Cells In Peripheral Blood Of Patients With Systemic Lupus Erythematosus And The Effect Of Low-dose IL-2 Treatment On IFN-α And NK Cells

Objective:1.To study peripheral blood IFN-αlevels,NK cell counts and absolute CD4⁺T cell subpopulation count levels in patients with systemic lupus erythematosus（SLE）.2.Analysis Correlations between IFN-αlevels and NK cell counts and their correlation with disease activity indicators were analyzed in SLE patients.3.To compare IFN-αexpression levels,NK cell count,and CD4⁺T cell subsets in SLE patients before and after short-term low-dose interleukin-2（Ld-IL 2）treatment.Methods:A total of 71 SLE patients diagnosed in the Rheumatology Department of the Second Hospital of Shanxi Medical University were selected as the study subjects,and tumor and other autoimmune diseases,as well as pregnant or lactating women,were excluded.At the same time,30 physical examination patients from the physical examination center at the same period were selected as healthy control group.Two tubes of fasting venous blood from these two groups were drawn in the morning,the IFN-αlevels were measured by the enzyme-linked immunosorbent assay in the first tube,the number of peripheral NK cells by flow cytometry,and the count of each subset of CT4⁺T cells.The clinical data（age,sex,initial diagnosis,course of disease）and related laboratory tests:erythrocyte sedimentation rate,C-reactive protein,complement C₃,C₄,ANA antibody titer and ds-DNA antibodies were collected.The SLE patient group was calculated into the low disease activity group,the low disease activity group（27 patients）and the moderate to high disease activity group（44patients）.The study content is divided into four parts:1.71 SLE patients and 30 healthy people were compared between the peripheral blood IFN-αlevels,absolute NK cell count and CD4⁺T lymphocyte subsets;2.The 71 patients were divided into the low disease activity group 27 and 44 in the moderate to high disease activity group and included in healthy subjects to compare the differences in IFN-αlevels,absolute NK cell count and CD4⁺T lymphocyte subsets among the three groups.3.The correlation between IFN-αlevels and NK cell count and their correlation with disease activity indicators were analyzed separately.4.In the group of 71 patients with SLE,49 patients were selected,On the basis of standard treatment（including glucocorticoids,immunosuppressants,biological agents,or combination use）,low dose IL-2 was added to short-term treatment,（50WIU,subcutaneous injection,continuous use for 5 days）,was compared to the changes of IFN-αexpression level,NK cell count,and CD4⁺T lymphocyte subset count in SLE patients before and after Ld-IL 2 treatment.Results:1.In SLE patients,the IFN-αlevel in peripheral blood increased,and the absolute count of NK cells and the absolute count of CD4⁺T cells decreased,the difference was statistically significant（P<0.001）;the Th2 cell count,Treg cell count and Th17/Treg cell ratio decreased,the difference was statistically significant（P<0.01）;the differences of Th1 cell count,Th17 cell count and Th1/Th2 cell ratio were not statistically significant（P>0.05）.2.Compared with healthy controls,low disease activity had increased IFN-αlevels,decreased absolute NK cell counts,the difference was statistically significant（P<0.05）,and no significant difference in CD4⁺T cell subsets（P>0.05）.Compared with the low-disease activity group,the moderate-high disease activity group,IFN-αlevels increased,the difference was statistically significant（P<0.05）,there was no significant difference in CD4⁺T cell subsets（P>0.05）.3.Peripheral blood IFN-αlevels in SLE patients were negatively correlated with absolute NK cell counts（r=-0.243,P=0.042）.IFN-αlevels were positively correlated with SLEDAI score（r=0.487,P<0.001）,ESR（r=0.438,P<0.001）,negative correlation trend with complement C₃levels,but the difference was not statistically significant（P>0.05）;Absolute NK cell counts were negatively correlated with SLEDAI score（r=-0.483,P<0.001）,ESR（r=-0.307,P=0.009）and positively with complement C₃levels（r=0.284,P=0.016）.4.After Ld-IL2 treatment,leukocytes,neutrophils,lymphocytes,and complement C₃were increased in SLE patients（P<0.01）;ESR and SLEDAI score were decreased（P<0.001）;the differences in platelets,C-reactive protein,and complement C₄before and after treatment were not statistically significant（P>0.05）.IFN-αlevel Th17/Treg cell ratio was decreased（P<0.05）,absolute NK cell count,absolute CD4⁺T cell count,absolute Th1cell count,absolute Th2 cell count,absolute Treg cell count increased（P<0.05）,and the differences in absolute Th17 cell count and Th1/Th2 cell ratio were not statistically significant（P>0.05）.Conclusions:1.The immune status of SLE patients was disturbed,IFN-αlevel increased in peripheral blood,NK cell count and CD4⁺T cell subset count decreased;2.IFN-αlevels and NK cell count in SLE;and both were correlated with disease activity;3.Short-term Ld-IL2 may improve the immune imbalance in SLE patients by restoring IFN-αlevels,NK cell counts and CD4⁺T cell subpopulation counts,but its long-term efficacy needs further study.