Pathogenesis Of Chronic Idiopathic Thrombocytopenic Purpura Research Articles

Correlation of Breg with CD4(+)T cells of peripheral blood in patients with CITP and its clinical significance

This study was aimed to detect the level of the peripheral blood Breg and CD4(+) T cell subgroups in patients with chronic idiopathic thrombocytopenic purpura (CITP) before and after therapy, and to analyse the charge of related cytokines and their correlation, to explore their roles in the pathogenesis of CITP. A total of 35 CITP cases were taken as the research group and 35 healthy persons were served as the control group. The peripheral blood mononuclear cells (PBMNC) were separated, the percentages of Th1, Th17, Th22 and Breg cells were detected by flow cytometry before and after treatment of glucocorticoid, and the IFN-γ, IL-17, IL-22 and IL-10 levels from PBMNC culture supernatant also were determined by ELISA. The results showed that there was significant difference as compared with the healthy controls, the proportion of peripheral blood Th1, Th17, Th22 cell subgroups all increased in CITP patients before treatment with glucocorticoid, the regulatory B cells (Breg) ratio was reduced, the differences had statistical significance (P < 0.05), but the differences were no statistically significant after treatment with glucocorticoid (P > 0.05). The levels of IFN-γ, IL-17, IL-22 from culture supernatant all increased in CITP patients before treatment, the level of IL-10 was lower than that of the healthy control, the difference was statistically significant (P < 0.05), but the there were no statistically significant differences after treatment (P > 0.05). There were positive correlation between the Breg cells and IL-10 expression in CITP patients (P < 0.05), the Breg cells and Th1, Th17, Th22 cells showed a negative correlation, IL-10 and IFN-γ, IL-17, IL-22 levels also showed a negative correlation. It is concluded that the down-regulation of regulatory B cells proportion and the IL-10 level may participate in the mechanism of CD4(+) T cell immunity disorder in CITP, which can provide new targets and ideas for the clinical immune regulation therapy.

Leptin enhances in vitro secretion of IgG antiplatelet antibodies by splenocytes and peripheral blood mononuclear cells from patients with chronic idiopathic thrombocytopenic purpura

Chronic idiopathic thrombocytopenic purpura (ITP) is an organ-specific autoimmune disease characterized by the production of antibodies against antigens on the membranes of platelets, resulting in enhanced destruction of the platelets by macrophages. Leptin, a cytokine-like hormone, plays a role in the pathogenesis of several autoimmune diseases. In this study, we observed significantly increased plasma leptin levels combined with decreased soluble leptin receptor (sOB-R) levels in 18 chronic ITP patients compared with 14 controls. We also demonstrated significantly elevated mRNA expression of long form leptin receptor (Ob-Rb) on peripheral blood mononuclear cells (PBMCs) from chronic ITP patients. Treatment with recombinant leptin or serum with high leptin levels enhanced in vitro secretion of IgG antiplatelet antibodies by splenocytes and PBMCs from patients with chronic ITP. After depletion of CD4+ T cells from splenocytes, leptin lost this function. Further studies showed that leptin could increase platelet reactive T cells. These findings suggest that leptin may be involved in the pathogenesis of chronic ITP and might offer a potential target for the treatment of this disease.

The effect of costimulatory factors in the pathogenesis of chronic idiopathic thrombocytopenic purpura.

To investigate the effect of costimulatory factors in the pathogenesis of chronic idiopathic thrombocytopenic purpura (CITP), we examined the expression of CD80 on platelets and megakaryocytes in patients with CITP and the controls by FACS. By using CD80 monoclonal antibody (McAb) to inhibit interaction among cells which is mediated by costimulatory factors, we observed the effect of CD80 McAb on the growth and maturation of megakaryocytic progenitors of patients with CITP in vitro. The results showed the expression of CD80 on platelets and megakaryocytes in CITP group was significantly higher than that in controls (P<0.01). There was a significantly positive correlation between the expression of CD80 on platelets and serum PAIgG in CITP (r=0.86, P<0.05). The mean of various clone numbers (CFU-MK, BFU-MK and mCFU-MK) in CITP were all lower than those in controls (P<0.05). In megakaryocytes co-cultured with CD80 McAb, there was an increasing tendency of the number of CFU-MK and big CFU-MK (the number of megakaryocyte with GP IIIa positive was more than 20) and mediate CFU-MK (the number of megakaryocyte with GP IIIa positive was 11-20). When the concentration of CD80 McAb was 10 microg/L, there was a significant difference in the number of megakaryocytic colony formation (CFU-MK, BFU-MK and mCFU-MK) between the group with CD80 McAb and that without it (P<0.05). These showed the abnormality of costimulatory factors had important effect in the pathogenesis of CITP.

The pathogenesis of chronic immune (idiopathic) thrombocytopenic purpura

Chronic immune (idiopathic) thrombocytopenic purpura (ITP) is an autoimmune disorder in which antiplatelet autoantibody induces platelet destruction. Platelet surface membrane proteins become antigenic, stimulating the immune system to produce autoantibody. The initial antigenic response probably occurs in the spleen, inducing autoantibody production followed by stimulation of other antibody-producing tissues, particularly the bone marrow. Autoantibodies against either platelet glycoprotein (GP)IIb/IIIa or GPIb/IX are produced by about 75% of ITP patients and can be detected using antigen-specific assays. The spleen is the major site of platelet destruction in ITP because of its unique milieu. About one third of the platelet mass is present in the spleen at all times, where the local production of antiplatelet antibody leads to high autoantibody concentrations. These antibody-sensitized platelets circulate slowly through the phagocytic cell-rich spleen, resulting in their destruction. Since autoantibody binds to both platelets and megakaryocytes, both platelet destruction and inhibition of thrombopoiesis may be of importance in the pathogenesis of chronic ITP.