The Study Of Circulating Immunomoderate Molecule Profiles In Idiopathic Thrombocytopenic Purpura

Objective: To evaluate the immune pathogenetic mechanism of Idiopathic or Immune Thrombocytopenic Purpra(ITP), the expression of T cell activation antigens such as CD 154 and CD69 as well as soluble CD 154 (sCD154), IL-4, IL-6 were investigated in ITP.Methods: The mAblBl against human CD154 was used as coating antibody, the other mAb4F1 recognized different epitope was labeled with Biotin. Then an ELISA kit for detecting sCD154 was set up. The percentages of CD4~+T cells expressing CD 154 and CD69 in peripheral blood of 30 ITP patients in comparison to 30 healthy controls were determined by two colour flow cytometry. The ELISA assay was used to detect the levels of sCD154, IL-4, IL-6 in ITP patients and healthy controls.Results: 1) Soluble CD 154 ELISA kit is successfully established with the sensitivity of 0.5ng/ml. The CV of kit is less than ±6.9% and the retrievable rate is 94.7-104.8% within three months as the kit stored in 4℃. It evidenced that the kit was of high sensitivity, stability and accuracy. In this study we measured sCD154 level of plasma and serum of 30 healthy children by this ELISA assay and found the sCD154 level of plasma(2.81 ±1.19 ng/ml) was about one fourth of that of serum(9.23 ±4.64 ng/ml). These data demonstrate that platelet seems to be a main contributor to sCD154, but not the only source of sCDl 54 in serum dependent on status of platelet and T lymphocyte. 2) The expressions of CD154 (16.7%±8.1%) and CD69 (13.9%±7.1%) on CD4+T cells in ITP were much higher than that of healthy controls. 3) The plasma levels of IL-4(18.57±9.3pg/ml) and IL-6(19.24±8.87 pg/ml) in ITP before therapy evaluated by ELISA were much higher than that of healthy controls and decreased to normal levels with immunosuppressive therapy.Conclusions: All these results showed that there were high expressions of CD 154 and CD69 on CD4+T cells indicating the CD4+T cells were activated in ITP. SolubleCD 154 ELISA kit was of high sensitivity, stability and accuracy. Platelet seems to be a main contributor to sCD154, but not the only source of sCD154 in serum dependent on status of platelet and T lymphocyte. The high concentrations of sCD154> IL-4 and IL-6 in ITP patients serum play a critical role in ITP immunol pathology.