ABSTRACT
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 PsA patients were randomly selected and treated with low dose IL-2 (5 ×105 U/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 by regulatory T cell(Treg) and T helper cell 17(Th17). Wilcoxon rank sum test, χ2 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/μl] was higher than that of the control group [5.9(4.0, 8.6) cells/μl] (Z=-1.997, P=0.046), the number of Treg cells [25 (17, 36) cells/μl] decreased compared with the control group [30 (23, 40) cells/μl] (Z=-2.957, Z=0.003), T/Treg [50 (36), 76)], B/Treg [7.6 (5.4, 11.5)], CD4+T/Treg [27 (21, 42)], CD8+T/Treg [20 (12, 30)], Th17/Treg [0.34(0.13, 0.51)], Th1/Treg [4.4(2.3, 7.2)], Th2/Treg [0.34(0.20, 0.53)], compared with control group T/Treg [40 (32, 54)], B/Treg [6.5 (4.2, 8.1)], CD4+T/Treg [20 (17, 25)], 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 (Z=-3.365, -3.217,-5.285, -2.097, -1.69, -1.482, -2.304, 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/μl] to [11 (7, 20) cells/μl, Z=-2.808, P=0.005] after low-dose IL-2 treatment, Treg cells increased from [27 (15, 30) cells/μl] to [71 (37, 98) cells/μl, Z=-3.945, P<0.01]. Because the growth rate of Treg was much higher than Th17, Th17/Treg [before IL-2 treatment: 0.26 (0.11, 0.44), after IL-2 treatment: 0.14 (0.1, 0.35)] returned back to the normal range. After the treatment with IL-2, the patient's 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 devel-opment of PsA. 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 condition and good safety.