[Expression of interleukin-22 and relative CD4(+) T cell subsets in patients with immune thrombocytopenia]

The aim of this study was to detect the expression of interleukin-22 (IL-22) and relative CD4(+) T cell subsets in untreated adult patients with immune thrombocytopenia (ITP), and to explore their roles in the pathogenesis of ITP. Fourty adult active ITP patients were enrolled in this study and 40 healthy subjects were taken as control. Plasma IL-22 level was quantified by ELISA. The percentages of Th1, Th17 and Th22 cells in peripheral blood were determined by flow cytometry. The Pearson correlation test was used to evaluate correlations between IL-22 level and Th1 cells, Th17 cells and Th22 cell percentages. The results showed that the plasma IL-22 levels in untreated ITP patients [(364.12 ± 94.22) pg/ml] were significantly higher than that in healthy controls (P < 0.001). The percentages of both Th1 [(18.92 ± 6.03)%] and Th22 [(2.28 ± 0.51)%] cells in ITP patients were elevated as compared to healthy controls (P < 0.05). Elevated plasma concentration of IL-22 positively correlated to the percentages of Th1 (r = 0.42, P = 0.022) and Th22 (r = 0.40, P = 0.030) cells in untreated ITP patients. The percentage of Th17 cells was not significantly different between untreated patients and normal controls, and there was no statistical correlation between the IL-22 level and the percentage of Th17 cells in active ITP patients. It is concluded that elevated IL-22 level correlates to Th1 and Th22 cells percentage, which may play a synergistic effect in the immunopathogenesis of ITP, while Thl7 cells may not be associated with the occurrence of active ITP.