CHARACTERISTIC OF TIM-3 EXPRESSION IN T CELL SUBSETS IN PATIENTS WITH IMMUNE THROMBOCYTOPENIC PURPURA

Abstract

T cell dysregulation is a common event involved in immune thrombocytopenic purpura (ITP). Recent findings indicated that aberrant expression of immune checkpoints may be related to autoimmune disease pathogenesis as well as in ITP. However, the distribution of Tim-3 and its co-expression with exhausted phenotype in T cell subsets remain unclear. In this study, the frequency of T-cell immunoglobulin mucin 3 (TIM-3) expression and co-expression with CD244 and CD57 in CD3+, CD4+ and CD8+ T cells were evaluated in peripheral blood (PB) from 16 cases with ITP and 21 healthy individuals (HI). Overall, the frequency of Tim-3+CD3+, CD4+ and CD8+T cells in ITP is similar to HI. However, Tim-3+CD244+CD8+ and Tim-3+CD57+CD8+T cells were increased in ITP in compared with HI group. While the percentage of CD244+ and CD57+CD3+, CD4+ or CD8+T cells was similar between ITP and HI groups. Moreover, the Tim-3+CD244+CD3+ and Tim-3+CD244+CD8+ T cells in newly diagnosed ITP group were higher than that in relapsed ITP group, similar trends showed in Tim-3+CD57+CD3+T cells. Obviously, relative higher Tim-3+T cells in most T cell subsets were detected in a case with acute ITP with viral infection. The distribution of Tim-3+ T cells in different subsets was also compared between PB and bone marrow (BM). High trends of Tim-3+T cells was detected in BM group. In conclusion, we firstly characterized T cell immune disorder with higher level of Tim-3+exhausted+CD8+T cells in ITP, the effect and mechanism of such alteration in ITP is needed further investigation.