Expression of CD40L in CD4+ T Cells From Patients with Primary Immune Thrombocytopenia

• 1、Institute of hematology & Blood disease hospital,Chinese Acadamy of medical science

Abstract：CD40/CD40 ligand (CD40/CD40L) was one of the important costimulatory molecules,and shown to play a significant role in the maintenance of autoimmunity. Nowadays, it was foundthat CD40L is over-expressed in CD4+ T cells of some female patients. Thus,in this study, weexplored the expression levels and roles of CD40L in CD4+ T cells from primary immunethrombocytopenia (ITP) patients. Plasma soluble CD40 ligand (sCD40L) levels were measured in44 active ITP patients, 12 patients in remission and 26 healthy controls by ELISA, and the resultshowed that active ITP patients had significantly elevated plasma sCD40L levels than those ofpatients in remission (p<0.05) and normal controls (P<0.05). In active ITP patients, the plasma?sCD40L levels showed significantly positive correlation with platelet counts (r=0.7721, p<0.0001). We further detected the CD40L protein on the surface of CD4+ T cells by flow cytometric analysis and CD40L mRNA expressions in CD4+ T cells by real-time PCR, and found both the CD40LmRNA and protein expression in CD4+ T cells were significantly elevated in active ITP than those of patients in remission (p<0.05) and normal controls (P<0.05). In addition, the CD40L mRNA and protein expression in CD4+ T cells from female ITP patients were higher than those of female healthy controls (P=0.037). In conclusion, the active ITP patients had significantly elevated serum sCD40L levels and CD40L expression on CD4+ T cells than those of patients in remission andnormal controls, which suggested that CD40L abnormal expressions were involved in ITP. Moreover, CD40L over-expression in CD4+ T cell of female patients but not males may be one of the important reasons for female susceptibility to ITP.????

Keywords： Primary immune thrombocytopenia；CD40 ligand；CD4+ T-lymphocytes