BKV‐specific T cells in the treatment of severe refractory haemorrhagic cystitis after HLA‐haploidentical haematopoietic cell transplantation

Background Haemorrhagic cystitis caused by BK virus (BKV) is a known complication of allogeneic haematopoietic cell transplantation (HCT) and is relatively common following HLA‐haploidentical transplantation. Adoptive immunotransfer of virus‐specific T cells from the donor is a promising therapeutic approach, although production of these cells is challenging, particularly when dealing with low‐frequency T cells such as BKV‐specific T cells. Case report Here, we present a patient who, following haploidentical HCT, developed severe BKV haemorrhagic cystitis, resistant to standard therapy. He responded well to adoptive transfer of donor cells enriched in BKV‐specific T cells using the new second‐generation CliniMACS Prodigy and the Cytokine Capture System from Miltenyi Biotec. Treatment led to full resolution of both the symptoms and viraemia without unwanted complications. Conclusion Our observations suggest that use of products enriched with BKV‐specific T cells generated using this system is safe and efficient in HLA‐haploidentical HCT where BKV cystitis can be a serious complication.