Alterative Expression Pattern of T Cell Immunosuppressive Receptors in Peripheral Blood of Patients with ITP

Immune Thrombocytopenia (ITP) is an autoimmune disorder characterized by production of auto-antibodies against platelet antigens. Dysregulation of T cells is a major role involved in this disease, while anti-platelet antibodies induce platelets destruction due to an imbalanced immune response. Increasing data showed that abnormal expression of T cell immunosuppressive receptors such as Programmed death 1 (PD-1) and Cytotoxic T lymphocyte antigen-4 (CTLA-4) may relate to autoimmune disease pathogenesis. In this study, we analyzed the expression levels of T cell immunosuppressive receptors including PD-1, PD-L1, CTLA-4, T cell immunoglobulin mucin 3 (Tim-3), lymphocyte activation gene-3 (LAG-3) and B and T lymphocyte attenuator (BTLA) in RNA from peripheral blood mononuclear cells (PBMCs) of ITP patients (18 cases, male: 12, female: 6, median age: 38.5 years, range 24-68 years), PBMCs from 20 healthy individuals were served as control group, by real-time PCR. The results showed that significant lower expression levels of PD-1 (median: 0.0015) and PD-L1 (median: 0.0572) were showed in ITP group in comparison with healthy group (PD-1, median: 0.0117, p < 0.0001; PD-L1, median: 0.5428, p < 0.0001), while the expression levels of Tim-3 (median: 0.1352), LAG-3 (median: 0.1403) and BTLA (median: 0.1403) were significant higher than that from healthy group (Tim-3, median: 0.0751, p < 0.007; Lag-3, median: 0.0155, p < 0.0001; BTLA, median: 0.0315, p < 0.0001). There was not significant different on the CTLA-4 expression level between ITP group (median: 0.0818) and healthy group (median: 0.1667) (p = 0.219). In conclusion, we firstly described the alterative expression pattern of T cell immunosuppressive receptors in ITP, which may have a role in ITP pathogenesis.