CHU de Bordeaux, Laboratoire d'Immunologie et Immunogénétique, Hôpital Pellegrin, Bordeaux, France.
Université de Bordeaux, Bordeaux, France.
HLA. 2018 Jun;91(6):507-513. doi: 10.1111/tan.13263.
HLA antibody detection with single antigen flow beads (SAFB) assays is impaired by complement interference whose frequency, predictability and distribution among HLA antigens have not been analyzed in large cohorts. We compared in two patients' cohorts the routine follow-up SAFB profiles obtained in class I (n = 129) and class II (n = 85) with and without ethylenediaminetetraacetic acid (EDTA)-treatment. The presence of complement interference was defined according to the reproducibility of the SAFB assays evaluated with our class I and II routine positive control sera. Interference occurred in 29.5% and 45.9% of patients in class I and II, respectively. In the untreated condition, at serum level, neither the number of positive beads, the highest bead mean fluorescence intensity (MFI) nor MFI at bead level, satisfactorily predicted interference. HLA-C were the least affected among class I beads. HLA-DQ beads were the most affected in class II. At least one antibody specificity was falsely negative without EDTA for about 3% of sera in class I and 9% in class II. EDTA-treatment did not significantly modify the low-MFI strengths (500-3000 range). This study emphasizes the high frequency of complement interference and the importance and advantages of systematically pretreating sera with EDTA before performing SAFB assays.
HLA 抗体的单抗原流（SAFB）检测会受到补体干扰的影响，但其在大样本中的频率、可预测性和在 HLA 抗原中的分布尚未得到分析。我们在两名患者队列中比较了未经 EDTA 处理（n=129）和经 EDTA 处理（n=85）的 I 类和 II 类 SAFB 常规随访谱。根据我们的 I 类和 II 类常规阳性对照血清评估的 SAFB 检测的可重复性来定义补体干扰的存在。在 I 类和 II 类患者中，分别有 29.5%和 45.9%的患者存在干扰。在未经处理的情况下，血清水平上，阳性珠的数量、最高珠平均荧光强度（MFI）或珠水平上的 MFI 均不能很好地预测干扰。I 类珠中 HLA-C 受影响最小。在 II 类中，HLA-DQ 珠受影响最大。约有 3%的 I 类血清和 9%的 II 类血清未经 EDTA 处理时，至少有一种抗体特异性呈假阴性。EDTA 处理并没有显著改变低 MFI 强度（500-3000 范围）。本研究强调了补体干扰的高频率，以及在进行 SAFB 检测前系统地用 EDTA 预处理血清的重要性和优势。
