Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Hum Immunol. 2013 Jan;74(1):32-40. doi: 10.1016/j.humimm.2012.10.012. Epub 2012 Oct 13.
Virtual crossmatching based on single-antigen bead (SAB) assays for the detection of donor-specific antibodies (DSA) has limited accuracy of predicting complement-dependent cytotoxicity crossmatch (CDCXM) results. In this study, 672 crossmatch combinations (32 allosensitized patients tested against cells from 21 high resolution-typed individuals) were analyzed to assess the potential of modified SAB tests in predicting T- or B-cell-CDCXM outcomes. Test modifications included measurement of C4d-fixation to detect complement-activating DSA ([C4d]DSA), or addition of dithiotreitol to abrogate the prozone effect ([IgG/DTT]DSA). Receiver operating characteristic (ROC) analysis revealed superior predictive accuracy of [C4d]DSA detection. Computing the mean fluorescence intensity (MFI) sum value of HLA class I [C4d]DSA in relation to T-cell-CDCXM revealed an area under the ROC curve (AUC) of 0.81. Other parameters, including DSA MFI maximum or number, were less predictive. Computing MFI sum values, AUC levels were lower for [IgG/DTT] (0.77) or [IgG]DSA detection (0.72), and did not considerably increase upon combining classifiers ([C4d] plus [IgG/DTT]: 0.82). ROC analysis revealed that [C4d]DSA detection (HLA class II) was also better at predicting B-cell-CDCXM results, even though, at very low MFI thresholds, the assay was found to provide comparably lower levels of specificity. Overall, B-cell-CDXM prediction was less precise, but could be enhanced by adjusting CDCXM thresholds to higher levels. Our data suggest particular efficiency of solid-phase complement detection as a tool for virtual crossmatching.
基于单抗原珠（SAB）检测的虚拟交叉配型对预测补体依赖性细胞毒性交叉配型（CDCXM）结果的准确性有限。在这项研究中，分析了 672 个交叉配型组合（32 名全致敏患者对 21 名高分辨率分型个体的细胞进行检测），以评估改良 SAB 检测在预测 T 或 B 细胞-CDCXM 结果方面的潜力。测试的修改包括测量 C4d 固定以检测补体激活的供体特异性抗体（[C4d]DSA），或添加二硫苏糖醇以消除前区效应（[IgG/DTT]DSA）。接收者操作特征（ROC）分析显示，[C4d]DSA 的检测具有更高的预测准确性。计算 HLA Ⅰ类 [C4d]DSA 与 T 细胞-CDCXM 相关的平均荧光强度（MFI）总和值，ROC 曲线下面积（AUC）为 0.81。其他参数，包括 DSA MFI 最大值或数量，预测性较差。计算 MFI 总和值时，[IgG/DTT]（0.77）或 [IgG]DSA 检测（0.72）的 AUC 水平较低，并且通过组合分类器（[C4d]加 [IgG/DTT]：0.82）没有显著增加。ROC 分析表明，[C4d]DSA 的检测（HLA Ⅱ类）在预测 B 细胞-CDCXM 结果方面也更好，尽管在非常低的 MFI 阈值下，该检测被发现提供了相对较低的特异性水平。总体而言，B 细胞-CDXM 的预测精度较低，但通过将 CDCXM 阈值调整到更高水平，可以提高预测精度。我们的数据表明固相补体检测作为虚拟交叉配型工具的效率特别高。
