Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Ann Lab Med. 2021 Jul 1;41(4):429-435. doi: 10.3343/alm.2021.41.4.429.
Pretransplant crossmatch (XM) testing is widely used for detecting preformed donor-specific antibodies (DSAs) against human leukocyte antigen (HLA). However, in some cases, there is a positive XM result in the absence of HLA-DSAs, the cause of which was rarely identified. We reviewed the causes of sequential positive XM results at a single center and analyzed the presence of non-HLA antibodies in patients with an unexplained positive pretransplant XM result. Among 251 patients with T-cell/B-cell complement-dependent cytotoxicity (CDC) or flow cytometric crossmatch (FCXM) positivity, HLA-DSAs were confirmed in 88 (35.1%) by a single antigen bead (SAB) assay, 150 (59.8%) used rituximab (anti-CD20), and 13 (5.2%) had neither HLA-DSAs nor a desensitization history. Anti-angiotensin II type 1 receptor IgG and 33 non-HLA antibodies were tested in the 13 patients with an unexplained positive pretransplant XM result, and more than one non-HLA antibody were revealed in all these patients; 11 patients had non-HLA antibodies reported to be associated with graft rejection, and two patients experienced rejection episode after kidney transplantation. Our study suggests considering non-HLA antibodies testing when a CDC or FCXM test is positive without a definite cause. Assessing non-HLA antibodies might be useful for interpreting XM results and evaluating immunologic risk in transplant recipients.
移植前交叉配型（XM）检测广泛用于检测针对人类白细胞抗原（HLA）的预先形成的供体特异性抗体（DSA）。然而，在某些情况下，即使不存在 HLA-DSA，也会出现 XM 阳性结果，其原因很少被确定。我们回顾了单一中心连续 XM 阳性结果的原因，并分析了移植前 XM 阳性结果原因不明的患者中是否存在非 HLA 抗体。在 251 例 T 细胞/B 细胞补体依赖性细胞毒性（CDC）或流式细胞交叉配型（FCXM）阳性的患者中，通过单抗原珠（SAB）检测在 88 例（35.1%）中确认了 HLA-DSA，150 例（59.8%）使用利妥昔单抗（抗-CD20），13 例（5.2%）既没有 HLA-DSA 也没有脱敏史。在 13 例移植前 XM 阳性结果原因不明的患者中检测了抗血管紧张素 II 型 1 受体 IgG 和 33 种非 HLA 抗体，所有这些患者均显示出一种以上的非 HLA 抗体；11 例患者的非 HLA 抗体与移植物排斥反应有关，2 例患者在肾移植后发生排斥反应。我们的研究表明，当 CDC 或 FCXM 检测阳性且无明确原因时，应考虑进行非 HLA 抗体检测。评估非 HLA 抗体可能有助于解释 XM 结果并评估移植受者的免疫风险。
