Study On The Role Of T Lymphocyte Subsets And Dendritic Cell Subsets In The Pathogenesis Of Immune Thrombocytopenia

Background Immune thrombocytopenia is a common autoimmune disease characterized by humoral and cellular immunity induced and resulting in platelet destruction bleeding disorders in hematology department. Studies have found that both proportion and function of T lymphocyte subsets and dendritic cell subsets in the pathogenesis of ITP are disordered. DC is the most powerful antigen-presenting cells(APC) found in ITP patients, immature DC mainly as immune surveillance, when inflammation or damagement occur, It can induce immature DC to mature and migrate DC to the lymphoid tissue. DC reach to the local lymphoid tissue has a strong antigen-presenting role. In this experiment the expression level of T lymphocyte subsets and DC subsets and the costimulatory molecules in the peripheral blood of patients with ITP were detected by flow cytometry(FCM), and compare the difference before and after treatment whether was statistically significant, and further analyze the relationship between the expression of CD4+T, CD8+ T lymphocyte cells and dexamethasone.Methods a total of 60 ITP patients(42 females and 18 males,the median age 36(18-63)) were recruited for the present study, ITP patients with newly diagnosed 18 cases, persistent ITP patients 19 cases and chronic ITP patients 23 cases. All patients were treated with high-dose dexamethasone therapy(40mg*4d, intravenous infusion), and severely ill patients parenteral administration of dexamethasone. Collecting blood samples of ITP patients before and 4 weeks after treatment and normal controls with heparin anticoagulation and distribution of T lymphocyte subsets and DC subsets in the peripheral blood of patients with ITP and normal controls were detected by flow cytometry, and retrospective analysis the relationship between the expression of CD4+T, CD8+ T lymphocyte cells and dexamethasone.Results The percentage of CD3+T lymphocyte and CD4+T lymphocyte in ITP patients were significantly decreased compared with control group(P <0.05). The percentage of CD8+T lymphocyte in ITP patients was significantly higher than control group(P <0.05). Compared with control group, the expressions of CD4+T lymphocyte were decreased and the CD8+T lymphocyte were increased in effective dexamethasone group(Ps < 0.001); The percentage of CD4+T lymphocyte had no difference and CD8+T lymphocyte were decreased(P<0.05) in ineffective dexamethasone group when compared with control group. The percentage of DC2 was increased in ITP patients compared with control group( P< 0.05) and there was no statistically after dexamethasone treatment; The expression of CD80 on DC1 and DC2 were increased compared with control group( P < 0.05), as well as the expression of CD86 on DC2 and the percentage of them decreased after treatment.Conclusions The disorder of expression and function in T lymphocyte and dendritic cell both could play important roles in the pathogenesis of ITP patients. There was a probable key relationship between the percentage of CD4+T and CD8+T lymphocyte and effects of dexamethasone.