T Follicular Helper Cells In Peripheral Blood Of Patients With Immune Thrombocytopenic Purpura

Background: T follicular helper cells(Tfh) is a new subset of T cells which is distinguished from Th1 and Th2 cells. It provides a helper function to B cells and represents one of the most numerous and import subsets of effector T cells in lymphoid tissues. Tfh has several features including chemokine receptor expression (CXCR5), location/migration (B cell follicles), and function (B cell help). Central to the function of Tfh cells is IL-21, a "helper" cytokine produced by Tfh cells that potently stimulates the differentiation of B cells into Ab-forming cells through IL-21R. Dysregulation of Tfh cell function, and over- or under-expression of Tfh cell-associated molecules such as ICOS or IL-21, most likely contributes to the pathogenesis of certain autoimmune diseases or immunodeficiencies or some cancers. Immune thrombocytopenic purpura (ITP) is an organ-specific autoimmune hemorrhaqic disease, which is characterized by a low platelet count(PLT). It is a common disorder which is characterized by autoantibody-mediated thrombocytopenic, and the major autiantigens are platelet glycoproteins. With the development of immunology, some researches have showed that cell-mediated immunity played an important role in the pathogenesis of ITP and the platelet destruction could also result from cellular immunity. Our study investigated the role Tfh played in pathogenesis of ITP patients and the new T cell subset Tfh might be related to ITP.Methods: 25 patients with ITP and 20 healthy adults without immunologic diseases or infectious disorders were chosen in our study. Peripheral blood was stained with anti- CD4-FITC and anti-CXCR5-PerCP. For cell surface staining, both Abs were added and cells were stained for 30 minutes. Stained cells were examined by flow cytometric.Results: The ratio of CXCR5~+CD4~+ T cells in ITP patients is significantly higher than that in the control group[(13.3±0.98)% VS (9.6±0.30) P<0.05].Conclusion: The ratio of Tfh increased in ITP patients. Tfh might play a role in evaluation and treatment of ITP.