Analysis of Frequencies and Subsets of Peripheral Helper T Cells in Patients with Immune Thrombocytopenia

Abstract

To investigate the frequencies and subset distribution of peripheral helper (Tph) T cells in patients with immune thrombocytopenia (ITP), and explore the pathogenesis of ITP. A total of 25 newly diagnosed ITP patients treated in The Second Affiliated Hospital of Dalian Medical University from January to December 2022 were selected, and 25 healthy volunteers (age- and sex-matched) were recruited as the control group. Flow cytometry was used to detect the subsets of CD4+ T cells and Tph cells. The frequency of effector memory (CCR7- CD45RO+CD4+) T cells in ITP patients was significantly higher than that in healthy controls(P < 0.05). The frequency of Tph cells in ITP patients was also significantly higher than that in healthy controls (P < 0.001), and most of the Tph cells in ITP patients were effector memory T cells. Furthermore, the expressions of T-cell costimulatory molecules in Tph cells, including ICOS and CD84, were similar to those in follicular helper T(Tfh) cells. CXCR3 - CCR6 -Tph (Tph2) subgroup was dominant in Tph cells, but the frequency of CXCR3+CCR6- Tph (Tph1) cells in ITP patients was much higher than that in healthy controls (P < 0.05). Tph cells, especially Tph1 cells, were abnormally expanded in ITP patients, which may be a potential etiology of ITP.