Development and characterization of a cell donor registry for virus-specific T cell manufacture in a blood bank

Adoptive cell therapy using virus-specific T cells (VST) is a strategy for treating common opportunistic viral infections after transplantation, particularly when these infections do not resolve through antiviral drug therapy. The availability of third-party healthy donors allows for the immediate use of cells for allogeneic therapy in cases where patients lack an appropriate donor. Here, we present the creation of a cell donor registry of human leukocyte antigen (HLA)-typed blood donors, REDOCEL, a strategic initiative to ensure the availability of compatible cells for donation when needed. Currently, the registry consists of 597 healthy donors with a median age of 29 years, 54% of whom are women. The most represented blood groups were A positive and O positive, with 36.52% and 34.51%, respectively. Also, donors were screened for cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Almost 65% of donors were CMV-seropositive, while less than 5% were EBV-seronegative. Of the CMV-seropositive donors, 98% were also EBV-seropositive. High-resolution HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies were determined in the registry. Prevalent HLA alleles and haplotypes were well represented to ensure donor-recipient HLA-matching, including alleles reported to present viral immunodominant epitopes. Since the functional establishment of REDOCEL, in May 2019, 87 effective donations have been collected, and the effective availability of donors with the first call has been greater than 75%. Thus, almost 89% of patients receiving an effective donation had available at least 5/10 HLA-matched cell donors (HLA-A, -B, -C, -DRB1, and -DQB1). To summarize, based on our experience, a cell donor registry from previously HLA-typed blood donors is a useful tool for facilitating access to VST therapy.