Study Of Immunologic Function Of T Lymphocyte In Patients With Idiopathic Thrombocytopenic Purura

Aim:To investigate the role of T lymphocyte in the immunologic pathophysiology of ITP,we evaluated the apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes in idiopathic thromobocytopenic purura patients,and analyzed the percentage of CD8~+T lymphocyte and the expressional levels of CD8~+T lymphocyte's CX3CR1mRNA in patients of idiopathic thromobocytopenic purura.It maybe provide a new method to treat diseases.Methods:Firstly,flow cytometry was used to investigate the apoptotic percentage of CD3~+,CD4~+,CD8~+T lymphocytes from ITP patients.Then,we speparated peripheral blood mononuclear cells from ITP patients and normal controls and divided these PBMCs into A and B,A:plus in IL-2,B:plus in IL-2 and dexamethasone.After 24 and 48 hours of coculture,we harvestd the PBMCs and investigated the apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes.High dose dexamethasone(HD-DXM) was the initial treatment for ITP patients.When their platelet Counts were more than 100×10~9/L,we analyzed the apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes.The percentage of CD8~+T lymphocyte was analyzed in the peripheral blood of 1TP patients and nomal controls by flowcytometry as well.We isolated peripheral blood mononuclear cells,from which CD8~+T lymphocyte was selected using magnetic microbeads.The expressional levels of CD8~+T lymphocyte's CX3CR1mRNA was analyzed by RT-PCR.Results:The apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes were significantly lower in ITP patients than those in normal control group(P＜0.05,0.05,0.05). There were no significant differences in apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes between ITP patients in A and B group in 24 hours of culture (P＞0.05,0.05,0.05).However,those were significantly higher in B group than in A group in 48 hours(P＜0.05,0.01,0.01).In normal control group,the apoptotic percentages of CD3~+,CD4~+,CD8~+T lymphocytes were all significantly higher in B group than those in A group after 24 hours and 48 hours(P＜0.05).The apoptotic percentages' differences between A group and B group of CD3~+,CD4~+,CD8~+T lymphocytes were significantly lower in ITP patients than those in normal control group after 24 hours (P＜0.01,0.05,0.05),while there were no differences between ITP group and normal group after 48 hours(oP＞0.05,0.05,0.05).After treatment the apoptotic percentages of CD3~+,CD4~+,CD8~+Tlymphocytes became higher than before(P＜0.01,0.01,0.01).There were no significant differences in apoptotic percentages of CD3~+,CD4~+,CD8~+Tlymphocytes between normal controls and patients after treatment(P＞0.05,0.05,0.05).Conclusion:ITP patiens' apoptotic percentage of CD3+,CD4+,CD8+T lymphocytes reduce and resist to the action of dexamethasone-induced apoptosis.We also investigate the percentage of CD8+T lymphocyte and the expressional levels of CD8+T lymphocyte's CX3CR1mRNA those were significantly higher than normal controls in the peripheral blood of ITP patients.These tell us that the abnormality of T lymphocyte's apoposis and CD8+T lynphocyte's percentage may play a role in the in the immunologic pathophysiology of ITP.