The Absolute Number Of Peripheral Treg Cells In Patients With Psoriatic Arthritis And Short-term Efficacy And Safety Evaluation Of Low-dose IL-2

Objective:To study the expression of peripheral blood lymphocyte subsets in Psoriatic Arthritis(PsA)patients and the short-term efficacy of low doses of Interleukin-2(IL-2).Methods:Ninety-five patients with PsA were enrolled as study subjects and 106 healthy people as control group.On the basis of conventional treatment,a total of 22 PsApatients were randomly selected and treated with low dose IL-2(50WIU/d,continuously used for 5 days,IH),and the disease condition and lymphocyte changes were observed.Flow cytometry was used to detect the absolute count of T subsets dominated byregulatory T cell(Treg)and T helper cell(Th17).Wilcoxon rank sum test,?~2 test and Spearman correlation analysis were used for statistical analysis.Results:The absolute number of Th17 cells of PsA patients[7.2(4.0,12.8)cells/ul]was higher than that of the control group[5.9(4.0,8.6)cells/ul](Z=-1.997,P=0.046),the number of Treg cells[25(17,36)cells/ul]decreased compared with the control group[30(23,40)cells/ul](Z=-2.957,P=0.003),T/Treg[50(36,76)],B/Treg[7.6(5.4,11.5)],CD4~+T/Treg[27(21,42)],CD8~+T/Treg[16(11,24)],Th17/Treg[0.19(0.13,0.31)],Th1/Treg[3.5(1.8,5.8)],Th2/Treg[0.24(0.15,0.39)]were significantly increased(P<0.05).Treg cells were negatively correlated with disease activity indexes TJC[r=-0.213,p=0.038]、VAS[r=-0.299,p=0.003]、PHGA[r=-0.287,p=0.005]、DLQI[r=-0.208,p=0.043].Th17 cells increased from[6.3(2.3,11.5)cells/ul]to[10.1(7.0,20.0)cells/ul,Z=-2.808,P=0.005]after low-dose IL-2 treatment,Treg cells increased from[26.8(14.9,29.9)cells/ul]to[70.9(36.5,97.6)cells/ul,Z=-3.945,P<0.001].Because the growth rate of Treg was much higher than Th17,Th17/Treg[before IL-2:0.26(0.11,0.44)cells/ul,after IL-2:0.14(0.1,0.35)cells/ul]decreased back to the normal range.After the treatment with IL-2,the patient’s diseases activity indicators were significantly improved,and there were no reversible adverse reactions.Conclusion:The reduction of Treg cells may be involved in the occurrence and development of PsA,immune dysfunction caused by imbalance of Th17/Treg may play an important role in the process of PsA onset,and Treg cells were negatively correlated with disease activity.Low dose IL-2 treatment can effectively promote the proliferation of Treg cells and the recovery of Th17/Treg balance,which is conducive to the improvement of the disease.