前瞻性评价单克隆抗体俘获血小板抗原技术对免疫性血小板减少症的诊断价值

目的 评价单克隆抗体俘获血小板抗原技术(MAIPA)对免疫性血小板减少症(ITP)的诊断价值,以及对免疫性和非免疫性血小板减少的鉴别诊断价值.方法 以来自14家医院的321例血小板减少患者为研究对象,男118例,女203例,应用改良MAIPA试验双盲法检测患者血小板膜糖蛋白特异性自身抗体(抗-GPⅡb/Ⅲa和抗-GP Ⅰ b/Ⅸ),客观评价该试验在ITP诊断中的敏感性和特异性,了解ITP患者血小板特异性抗体浓度与血小板数量的相关性以及地塞米松治疗后抗体浓度的变化.结果 抗-GPⅡb/Ⅲa、抗-GP Ⅰ b/Ⅸ、抗-GPⅡb/Ⅲa联合抗-GP Ⅰ b/Ⅸ诊断ITP的敏感性分别为39.75%、32.64%、55.23%,特异性分别为97.56%、93.94%、92.68%,阳性预测值分别为97.94%、93.98%、95.65%,阴性预测值分别为35.71%、32.35%、41.53%,总有效率分别为54.51%、48.29%、64.80%;ITP患者血小板特异性抗体阳性率显著高于非免疫性血小板减少患者;抗体阳性患者的血小板数量显著低于阴性患者,ITP患者血小板特异性抗体水平吸光度(A)值]与血小板数量呈负相关;激素治疗有效的ITP患者抗-GPⅡb/Ⅲa或(和)抗-GP Ⅰ b/Ⅸ转阴或抗体水平降低.结论 MAIPA试验对ITP具有较高的诊断价值,对ITP患者的疗效也具有指导意义,可作为IFP和非免疫性血小板减少的鉴别诊断依据.

A prospective assessment of the diagnostic value of MAIPA test in idiopathic thrombocytopenic purpura

Objective To evaluate the clinical significance of MAIPA test in diagnosis of idiopathic thrombocytopenic purpura(ITP) and in the differential diagnosis of antoimmune thrombocytopenias from nonimmune thrombocytopenias. Methods A total of 321 thrombocytopenic patients (118 males, 203 females)from 14 centers were studied. A modified monoclonal antibody immobilization of platelet antigen (MAIPA)method was used to detect the platelet glycoprotein-specific autoantibodies ( anti-GP Ⅱ b/Ⅲ a, anti-GP Ⅰ b/Ⅸ ) to double-blindly evaluate its sensitivity and specificity for the diagnosis of ITP and to investigate the impact of the antibodies on platelet count. Results The results showed that for the diagnosis of ITP, anti-GP Ⅱ b/Ⅲ a , anti-GP Ⅰ b/Ⅸ and both of them had the sensitivity of 39.75%, 32.64% and 55.23%; the specificity of 97.56%, 93.94% and 92. 68%; the positive predictive value of 97. 94%, 93.98% and 95.65%; the negative predictive value of 35.71%, 32.35% and 41.53%; and the total efficiency of 54.51%, 48.29% and 64.80%, respectively. The positivity of the autoantibodies in immune thrombocytopenias was incredibly higher than that in nonimmune thrombocytopenias. The platelet counts in the immune thrombocytopenias with autoantibody positivities were significantly lower than those without the autoantibodies.The platelet counts were negatively correlated with the concentration of the autoantibodies. The levels of antiGP Ⅱ b/Ⅲ a or anti-GP Ⅰ b/Ⅸ or both of them dropped or disappeared in patients being responsive to steroid therapy. Conclusion MAIPA assay is proved to be of great value for the diagnosis of ITP and for differential diagnosis of immune thrombocytopenias from nonimmune thrombocytopenias.