Splenic irradiation combined with plasmapheresis and rituximab: a new option reducing donor-specific antibody in haploidentical hematopoietic stem cell transplantation

Abstract The development of donor-specific antibodies (DSAs) against human leukocyte antigens (HLA) is a major problem during haplo-identical hematopoietic stem cell transplantation (haplo-HSCT). There is currently no recommended treatment option to remove DSAs. Thus, we conducted a prospective, single-arm study where we combined low-dose splenic irradiation with plasmapheresis and rituximab as a new treatment protocol to reduce DSAs before haplo-HSCT. Nineteen patients were enrolled in this prospective study and matched controls treated with the same protocol, but without splenic irradiation, were simultaneously collected from DSA patients. The aim of this study is to explore the safety and efficacy of our outlined treatment protocol made up of splenic irradiation, plasmapheresis, and rituximab. We found that DSA levels decreased significantly after transplantation in both groups, however they decreased more greatly in patients treated additionally with splenic irradiation than those in control group. De novo DSAs were not detected after transplantation in the splenic irradiation group but detected in 5 patients from the control group. At follow-up, we found that patients in splenic irradiation group achieved superior overall survival (OS) and progress free survival (PFS) compared to those in control group. We concluded that adding low-dose splenic irradiation to routine protocol is feasible. chictr.org.cn: ChiCTR2100051456. Registered 24 September 2021. Retrospectively registered.