摘要目的 探讨HLA抗体的平均荧光强度值(MFI)预测补体C1q阳性的价值.方法 研究对象为2012年1月至2014年1月31例等待肾移植的高致敏患者,留取患者血清样本,采用单抗原磁珠法检测患者HLA抗体及C1q结合的HLA抗体,分析HLA抗体的MFI与C1q阳性的相关性.结果 31例患者中,单纯HLAⅠ类抗体阳性14例,单纯Ⅱ类抗体阳性12例,工、Ⅱ类抗体均阳性5例.Ⅰ类和Ⅱ类抗体的MFI分别为7 332±4 490和9 014±5 885.工类抗体中弱阳性、中度阳性和强阳性抗体分别为160个、190个和280个,Ⅱ类抗体则分别为132个、119个和285个.Ⅰ类抗体中有43.2％(272/630)的抗体能结合补体C1q,而Ⅱ类抗体为51.3％ (275/536) (P=0.006).C1q阳性HLA工类和Ⅱ类抗体的MFI(分别为11 052±3 291和13 347±4 076)显著高于C1q阴性HLAⅠ类和Ⅱ类抗体的MFI(分别为4 506±2 960和4 448±3 602)(P＜0.05).Spearman相关性分析显示,HLA抗体MFI与同一抗体C1q的MFI具有相关性,其中Ⅰ类抗体相关系数(r)=0.665,P＜0.01;Ⅱ类抗体r=0.761,P＜0.01.ROC分析显示,HLA抗体MFI能预测补体C1q阳性,其中工类抗体的曲线下面积(AUC)=0.917,Ⅱ类抗体的AUC=0.927.HLA Ⅰ类抗体MFI的截断值为8238,敏感性和特异性分别为82.4％和87.4％,阳性预测值为86.7％,阴性预测值为83.2％;Ⅱ类抗体MFI的截断值为6 754,敏感性和特异性分别为90.9％和82％,阳性预测值为83.5％,阴性预测值为90.0％.结论 HLA抗体的MFI能够预测补体C1q的结合.

abstractsObjective To investigate the relationship between HLA antibodies strength and complement-binding ability in sensitized renal patients waiting for renal transplantation.Method Serum samples of 31 sensitized renal patients waiting for renal transplantation were retrospectively analyzed by single-antigen bead array (SAB) to identify HLA antibodies and in parallel by C1q-SAB to determine the complement binding of HLA antibodies.Result C1q-positive HLA antibodies had significantly higher MFI than C1q-negative HLA antibody (for Class Ⅰ,11052 ± 3291 vs.4506 ± 2960,P＜0.05;for Class Ⅱ,13347 ± 4076 vs.4448 ± 3602,P＜0.05).The mean fluorescence intensities (MFI) of IgG-SAB were correlated with the MFI of C1q-SAB for the same antibodies (Spearman correlation; Class Ⅰ,r =0.665,P ＜ 0.01 ; Class Ⅱ,r =0.761,P ＜ 0.01).Receiver operating characteristics (ROC) curve analysis showed that the MFIs of HLA antibodies by IgG-SAB could predict their C1q-binding abilities [area under the curve (AUC)Class Ⅰ =0.917; AUCclass Ⅱ =0.927).Using MFI cut-off value of 8238 and 6754 for HLA Class Ⅰ and Class Ⅱ antibodies,respectively,the sensitivity and specificity for C1q binding were 82.4％ and 87.4％ for Class Ⅰ antibodies,and 90.9％ and 82％ for Class Ⅱ antibodies,respectively.Conclusion The MFI of HLA antibodies by IgG-SAB can predict the C1q binding capability at a certain extent before transplantation.