Aref Salah, Selim Tarek, Ibrahim Lamya, Abd-Elghaffar Hasan, Ashery Rsha El
Department of Clinical Pathology, Mansoura Faculty of Medicine, Mansoura, Egypt.
Indian J Hematol Blood Transfus. 2009 Sep;25(3):96-103. doi: 10.1007/s12288-009-0028-0. Epub 2009 Nov 12.
Immune thrombocytopenic purpura is an acquired disorder, in which accelerated platelet consumption is due to platelet autoantibodies. The aim of this study was to investigate the clinical value of platelet autoantibodies assay in children with ITP and to evaluate flow cytometry in the detection of platelet autoantibodies in comparison with monoclonal antibody specific immobilization of platelet antigen (MAIPA) assay. We measured platelet autoantibodies by flow cytometry and MAIPA in 18 children with ITP (6 acute, 7 chronic and 5 in remission), in addition to 5 healthy children with matched age and sex as a control group. Significant elevation of platelet-associated immunoglobulin G (PAIgG), PAIgM and PAIgA was demonstrated in children with acute ITP compared to controls and children with chronic ITP (P < 0.05). There was significant elevation of PAIgG and PAIgM in children with acute ITP compared to children with ITP in remission (P < 0.05). There was significant negative correlation between platelet count and PAIgG levels in ITP children (r = -0.717; P = 0.001). Flow cytometry found PAIgG in 94.4% of ITP children. MAIPA has detected platelet specific IgG autoantibodies in 83.3% of ITP children. ROC analysis revealed sensitivity of 94%, specificity of 57% with overall accuracy of 83% for detection of PAIgG by flow cytometry compared to MAIPA.
Platelet autoantibodies testing in ITP can discriminate acute from chronic forms of the disease and is helpful in follow up of patients. Determination of PAIgM in combination of PAIgG could be of interest in the investigation of ITP. Flow cytometry is a sensitive method of detection of platelet autoantibodies that could be used in screening of suspected ITP and should be followed by MAIPA assay in positive cases to establish the diagnosis.
免疫性血小板减少性紫癜是一种获得性疾病，其中血小板加速消耗是由血小板自身抗体引起的。本研究的目的是探讨血小板自身抗体检测在儿童免疫性血小板减少性紫癜（ITP）中的临床价值，并与血小板抗原单克隆抗体特异性固定法（MAIPA）检测相比，评估流式细胞术检测血小板自身抗体的情况。我们对18例ITP患儿（6例急性、7例慢性、5例缓解期）以及5例年龄和性别匹配的健康儿童作为对照组，采用流式细胞术和MAIPA检测血小板自身抗体。与对照组及慢性ITP患儿相比，急性ITP患儿的血小板相关免疫球蛋白G（PAIgG）、PAIgM和PAIgA显著升高（P<0.05）。与缓解期ITP患儿相比，急性ITP患儿的PAIgG和PAIgM显著升高（P<0.05）。ITP患儿血小板计数与PAIgG水平之间存在显著负相关（r=-0.717；P=0.001）。流式细胞术在94.4%的ITP患儿中检测到PAIgG。MAIPA在83.3%的ITP患儿中检测到血小板特异性IgG自身抗体。ROC分析显示，与MAIPA相比，流式细胞术检测PAIgG的敏感性为94%，特异性为57%，总体准确率为83%。
ITP中血小板自身抗体检测可区分疾病的急性和慢性形式，有助于患者的随访。联合检测PAIgM和PAIgG可能对ITP的研究有意义。流式细胞术是检测血小板自身抗体的一种敏感方法，可用于疑似ITP的筛查，阳性病例应随后进行MAIPA检测以确诊。
