Humoral alloimmunity mediated by anti‐human leucocyte antigen (HLA) antibodies is a major challenge in kidney transplantation and impairs the longevity of the transplanted organ. The immunological risk of an individual patient is currently mainly assessed by detection of HLA antibodies in the serum, which are produced by long‐lived bone marrow‐residing plasma cells. However, humoral alloimmunity is complex, and alloreactive memory B cells constitute an additional factor in the interplay of immune cells. These recirculating “silent” cells are responsible for the immunological recall response by differentiating into antibody‐producing cells upon antigen re‐encounter. Historically, due to the lack of appropriate and routinely applicable assays to determine the presence and HLA specificity of alloreactive memory B cells, their contribution to the humoral alloimmune response has clinically often been suspected but could not be determined. In this review, we give an overview of recent advances in techniques to detect alloreactive memory B cells and discuss their strengths and limitations. Furthermore, we summarize experiences with these techniques in alloimmunized individuals and transplant recipients, thereby emphasizing unmet needs to be addressed in future studies.

中文翻译：

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肾移植中 HLA 特异性记忆 B 细胞检测：见解和未来挑战

由抗人白细胞抗原 (HLA) 抗体介导的体液同种免疫是肾移植的主要挑战，并会损害移植器官的寿命。目前，个体患者的免疫风险主要通过检测血清中的 HLA 抗体来评估，这些抗体是由长寿命的骨髓浆细胞产生的。然而，体液同种免疫是复杂的，同种异体反应性记忆 B 细胞构成了免疫细胞相互作用的额外因素。这些再循环的“沉默”细胞通过在抗原再次遇到时分化为产生抗体的细胞来负责免疫回忆反应。从历史上看，由于缺乏适当和常规适用的检测方法来确定同种异体反应性记忆 B 细胞的存在和 HLA 特异性，临床上经常怀疑它们对体液同种免疫反应的贡献，但无法确定。在这篇综述中，我们概述了检测同种异体反应性记忆 B 细胞技术的最新进展，并讨论了它们的优势和局限性。此外，我们总结了在同种免疫个体和移植受者中使用这些技术的经验，从而强调在未来的研究中需要解决未满足的需求。