The Clinical Significance Of Determination Of Glucoprotein â…¡b/â…¢a Autoantibodies By Cytometric Bead Array In The Diagnosis Of Idiopathic Thrombocytopenic Purpura

Background：Primary immune thrombocytopenia is a common clinical hemorrhagic disease, pathogenesis is not fullyclear.Now ITP is a such disease which thought humoral immunity and cellular immune abnormality causeplatelet destruction increased, decreased production and finally characterized by peripheral blood plateletreduction, skin and mucous membrane bleeding. At present, the diagnosis of ITP is exclusionary, have no"gold standard",and does not to diagonse until eliminate autoimmune diseases and other reasons caused bysecondary thrombocytopenia. So a high specificity of laboratory diagnosis index need established toconfirm the clinical diagnosis, and can identify immune and non immune thrombocytopenia. Currently,theplatelet specific antibodies are directed to platelet-specific receptors, primary GPⅡ b/Ⅱ a orGPIb/Ⅸ.Measurements of Platelet glycoprotein-specific autoantibodies have differert approach, mainlyincluding monoclonal antibody immobilization of platelet antigen (MAIPA) technique and radioactiveimmunobead assay.these assays have high specificity (78%-93%)which has a certain value for identifyingITP and non immune thrombocytopenia.However,these assays can not be widely used as their lowsensitivity(49-66%)and methodical limitations such as high-level laboratory conditions is requested,tedious operation and time consuming. Cytometric bead array is a new technology based on flowcytometry.Polystyrene microbeads coated with specific monoclonal antibodies can immobilize some lowmolecular weight substance insolution,so the contents of those substances are transformed into detectingsignals shown by flow cytometry.Scholars at home and abroad applied the cytometric bead array to detectthe platelet specific antibodies, its specificity and sensitivity are high in the diagnosis of ITP,Moreover,savetime and high reproducibility.Objective：To detect platelet glycoprotein IIb/IIIa autoantibodies by cytometric bead array, and its diagnosticsignificance in ITP.Methods：Patients with ITP and non immune thrombocytopenia and healthy controls are selected from The firstaffiliated Hospital of the Medical College,Shihezi University.Extracting these patients peripheral venousblood,then detecting platelet glycoprotein IIb/IIIa autoantibodies by cytometric bead array, recording eachsample mean fluorescence intensity (MFI). Last, individual fluorescence level was calculated as a ratio tothe three control. At the same time,peripheral blood T-lymphocyte cell subsets were mearused by flowcytometry.Results：1.The mean fluorescence intensity ratios in ITP group,non immune thrombocytopenia group and healthycontrols were （2.61±1.09）、（1.32±0.59）and（0.95±0.40）,respectively.The mean fluorescence intensityratios in ITP group was significantly higher than that of the latter two(P <0.01),However, there was nosignificant difference of mean fluorescence intensity ratios between non immune thrombocytopenia groupand healthy controls（P>0.05） 2.If the up limit of health controls were set as cutoff,ratios of larger than1.93were consideredpositive,cytometric bead array had a sensitivity of71.88%,a specificity was84.62%for the diagnosis ofITP.The ROC curve showed the diseriminative validity of cytometric bead array was0.848.3.In the detection of T lymphocyte subgroups, the percentage of CD3+T lymphocyte（63.81±8.23）%，CD4+T lymphocyte（32.89±7.24）%, and the ratio of CD4+/CD8+（1.32±0.48）in patients with ITPwere lower than those in healthy controls [（70.86±10.16）%、（41.39±6.41）%、（1.98±0.41）all p<0.05].The percentage of CD8+T lymphocyte （26.61±6.43）%in patients with ITP was higher than that ofhealthy control group（21.76±4.61）%(P <0.05).Conclusion:1.The sensitivity and specificity of cytometric bead array which applicated to detect platelet membranesurface glycoprotein autoantibodies were higher.and simple operation, good repeatability, has a certainpractical value in the auxiliary diagnosis of ITP.2.T lymphocyte subsets disorder involved in the pathogenesis of ITP, the test can be considered as ITPauxiliary index of clinical diagnosis.