Antigen-specific B cells in kidney transplantation

In this issue, Burton et al. describe a convincing method to identify and enumerate human leukocyte antigen-specific B cells and subsets using biotinylated human leukocyte antigen proteins. Importantly, they demonstrate that these antigen-specific B cells are found at a greater frequency in sensitized kidney transplant recipients when compared with healthy volunteers. Finally, using an indirect antigenspecific enzyme-linked immunosorbent spot assay, they uncover the complexity of B- and T-cell interactions and the influence of regulatory T cells on such interactions in vitro.