Laboratoire d'Immunologie et Histocompatibilité, Hôpital Saint Louis, Paris, France.
INSERM UMR 976 HIPI, Institut de Recherche Saint-Louis, Université de Paris, Paris, France.
HLA. 2023 Aug;102(2):157-167. doi: 10.1111/tan.15025. Epub 2023 Apr 17.
Several technical limitations of Luminex single antigen (LSA) assays have been described so far. This study focused on a reactivity pattern observed in many sera that cannot be explained by eplets described in the Epitope Registry database and sometimes appearing against a self-HLA allele or antigen. In most cases, this pattern is revealed by a discrepant result when compared with other assays (Luminex PRA, cell-binding assays such as flow cytometry cross match, LSA from another manufacturer…). We focus here on the Cw1/12/15 pattern appearing on the LABScreen class I LSA provided by One Lambda. We documented its behavior using this LSA after acid denaturation of the beads, using Lifecodes LSA from Immucor, and adsorption of sera either on spleen mononuclear cells from deceased donors or on single HLA transfected cell clones. We studied 33 sera from different patients positive for the three Cw beads, selected from our routine patients' LSA database. Nine patients had transplants from a Cw12 or Cw15 donor without any pejorative evolution of the graft, nor post-transplant MFI (mean fluorescence intensity) increase of the Cw1/12/15 beads. A significant increase of MFI was observed after acid denaturation of the LABScreen beads. All sera tested by Lifecodes LSA were negative for these Cw beads. Finally, we found no significant difference of MFI after adsorption on cells from either origin. Therefore, the Cw1/12/15 pattern appears to be a false positive reactivity of the LABScreen single antigen assay.
到目前为止，已经描述了 Luminex 单抗原 (LSA) 检测的几个技术限制。本研究集中在许多血清中观察到的反应模式上，这些模式无法用 Epitope Registry 数据库中描述的表位解释，有时也会针对自身 HLA 等位基因或抗原出现。在大多数情况下，与其他检测方法（Luminex PRA、细胞结合检测，如流式细胞交叉配型、来自另一家制造商的 LSA 等）相比，这种模式会显示出不一致的结果。我们在这里重点介绍 One Lambda 提供的 LABScreen 类 I LSA 上出现的 Cw1/12/15 模式。在用珠子进行酸变性后，使用 Lifecodes LSA 进行了分析，并使用来自已故供体的脾单核细胞或单个 HLA 转染细胞克隆吸附血清，我们记录了这种模式的行为。我们研究了从我们的常规患者 LSA 数据库中选择的 33 份来自不同患者的血清，这些患者的三种 Cw 珠子均为阳性。9 名患者接受了来自 Cw12 或 Cw15 供体的移植，移植物没有任何恶化，移植后 Cw1/12/15 珠子的 MFI（平均荧光强度）也没有增加。在用酸处理 LABScreen 珠子后，MFI 显著增加。用 Lifecodes LSA 检测的所有血清均为这些 Cw 珠子阴性。最后，我们发现吸附在源自任何来源的细胞后，MFI 没有显著差异。因此，Cw1/12/15 模式似乎是 LABScreen 单抗原检测的假阳性反应。
