HLA抗体的平均荧光强度值与补体C1q结合能力的相关性研究

Relationship between HLA antibodies strength and Clq binding ability

目的探讨HLA抗体的平均荧光强度值（MFI）预测补体Clq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Clq结合的HLA抗体，分析HLA抗体的MFI与Clq阳性的相关性。结果31例患者中，单纯HLtA工类抗体阳性14例，单纯Ⅱ类抗体阳性12例，Ⅰ、Ⅱ类抗体均阳性5例。Ⅰ类和Ⅱ类抗体的MFl分别为7332±4490和9014±5885。Ⅰ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Clq，而Ⅱ类抗体为51．3％（275／536）（P=0．006）。Clq阳性HLA工类和Ⅱ类抗体的MFI（分别为11052±3291和13347±4076）显著高于Clq阴性HLAⅠ类和Ⅱ类抗体的MFI（分别为4506±2960和4448±3602）（P〈O．05）。Spearman相关性分析显示，HLA抗体MFI与同一抗体Clq的MFI具有相关性，其中工类抗体相关系数（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Clq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。HLAⅠ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6754，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Clq的结合。

Objective 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 Clq-SAB to determine the complement binding of HLA antibodies. Result Clq-positive HLA antibodies had significantly higher MFI than Clq-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 Clq-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 Clq-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 1 and Class II antibodies, respectively, the sensitivity and specificity for Clq 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 Clq binding capability at a certain extent before transplantation.