The flow cytometric crossmatch is currently the gold standard for evaluating donor and recipient histocompatibility. The assay however does have limitations and is sensitive to false positive reactions resulting from the presence of non-HLA antibodies or therapy related immune biologics. Such false positive reactions can lead to the inappropriate decline of an acceptable donor organ or unnecessary therapeutic intervention. Here we describe the successful validation of anti-idiotype blocking antibodies in prevention of false positive flow crossmatch results caused by biologic therapy. Blocking antibodies specific for the Fab portion of Rituximab and/or Alemtuzumab were incubated with biologic containing patient serum prior to use in flow cytometric crossmatching. Biologic blocking successfully negated false positive crossmatch results with Rituximab (B cell ave. % change = -97%) or Alemtuzumab (T cell ave. % change = -99%, B cell ave. % change = -95%) infused sera respectively. Simultaneous blocking of these biologics was also successful. A complex case is presented to demonstrate the application of this procedure.

流式细胞术交叉匹配是目前评估供体和受体组织相容性的金标准。然而，该测定确实有局限性，并且对因非 HLA 抗体或治疗相关免疫生物制剂的存在而导致的假阳性反应敏感。这种假阳性反应可能导致可接受的供体器官的不当下降或不必要的治疗干预。在这里，我们描述了抗独特型阻断抗体在预防由生物治疗引起的假阳性流动交叉匹配结果方面的成功验证。在用于流式细胞术交叉配型之前，将特异于利妥昔单抗和/或阿仑单抗的 Fab 部分的封闭抗体与含有患者血清的生物制剂一起温育。分别使用利妥昔单抗（B 细胞平均变化百分比 = -97%）或阿仑单抗（T 细胞平均变化百分比 = -99%，B 细胞平均变化百分比 = -95%）分别使用生物阻断成功地否定了假阳性交叉匹配结果. 同时阻断这些生物制剂也很成功。提供了一个复杂的案例来演示该程序的应用。