Llorente S, Boix F, Eguia J, López M, Bosch A, Martinez H, Gonzalez M J, López-Hernández R, Salgado G, Moya-Quiles M R, Campillo J A, García-Alonso A M, Minguela A, Jimeno L, Alvarez-López M R, Muro M
Department of Nephrology, University Hospital Virgen Arrixaca, Murcia, Spain.
Transplant Proc. 2012 Nov;44(9):2535-7. doi: 10.1016/j.transproceed.2012.09.084.
There is no consensus about the impact of thresholds of complement-fixing antibody assays. Recently, a C1q-SAB assay has been developed to identify complement-fixing HLA antibodies with high sensitivity and specificity. Our aim was to determine the correlation between IgG single antigens beads (SAB) and C1q-SAB assay results among patients on the renal waiting list.
Serum samples from immunized renal waiting list patients as well as negative and positive controls were valided by Luminex (LMX). These sera, which were positive for 166 antibody specificities, were tested for HLA class I in parallel by LMX-IgG and LMX-C1q.
Comparison of antibody detection revealed no correlation based on median fluorescent intensity (MFI), levels between the IgG SAB and the C1qSAB assay (P > .05). IgG-positive sera with MFIs as low as 700 were able to fix C1q, whereas other sera with MFIs as high 14,500 did not. Furthermore, there appeared to be disparities in the profiles of class I antigens able to fix C1q-SAB. In our series, only 34% class I IgG SAB antibodies were also C1qSAB+. In several patients, we detected C1qSAB+ against IgGSAB- that was surely due to IgM antibodies. So, the C1qSAB assay detected IgM antibodies that fix complement.
These data suggested that the C1q-SAB assay could be an important method to evaluate pretransplant virtual crossmatch and to define nonpermitted specificities (C1q-fixing) in kidney transplantation.
关于补体结合抗体检测阈值的影响尚无共识。最近，一种C1q-SAB检测方法已被开发出来，用于以高灵敏度和特异性鉴定补体结合的HLA抗体。我们的目的是确定肾移植等待名单上患者的IgG单抗原珠（SAB）检测结果与C1q-SAB检测结果之间的相关性。
通过Luminex（LMX）对免疫的肾移植等待名单患者以及阴性和阳性对照的血清样本进行验证。对这些针对166种抗体特异性呈阳性的血清，通过LMX-IgG和LMX-C1q并行检测HLA I类。
基于中位数荧光强度（MFI）的抗体检测比较显示，IgG SAB检测与C1qSAB检测之间的水平无相关性（P>.05）。MFI低至700的IgG阳性血清能够结合C1q，而其他MFI高达14500的血清则不能。此外，能够结合C1q-SAB的I类抗原谱似乎存在差异。在我们的系列研究中，只有34%的I类IgG SAB抗体也是C1qSAB阳性。在几名患者中，我们检测到针对IgGSAB阴性的C1qSAB阳性，这肯定是由于IgM抗体所致。因此，C1qSAB检测可检测到能结合补体的IgM抗体。
这些数据表明，C1q-SAB检测可能是评估移植前虚拟交叉配型以及确定肾移植中不允许的特异性（C1q结合）的重要方法。
