BM is preferred over PBSCs in transplantation from an HLA-matched related female donor to a male recipient

The use of granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (PBSCs) and sex-mismatched hematopoietic cell transplantation (HCT), especially with female donors and male recipients (FtoM), is known to be associated with an increased risk of chronic graft-versus-host disease (GVHD) compared with transplantation with bone marrow (BM). This raises the question of whether the use of PBSCs in FtoM HCT might affect allogeneic responses, resulting in fatal complications. Using a Japanese transplantation registry database, we analyzed 1132 patients (FtoM, n 5 315; MtoF, n 5 260; sex-matched, n 5 557) with standard-risk diseases who underwent HCT with an HLA-matched related donor without in vivo T-cell depletion between 2013 and 2016. The impact of PBSC vs BM on transplantation outcomes was separately assessed in FtoM, MtoF, and sex-matched HCT. Overall survival (OS) and nonrelapse mortality (NRM) at 2 years post-HCT were significantly worse in patients with PBSCs vs those with BM in FtoM HCT (2-year OS, 76% vs 62%; P 5 .0084; 2-year NRM, 10% vs 21%; P 5 .0078); no differences were observed for MtoF or sex-matched HCT. Multivariate analyses confirmed the adverse impact of PBSCs in FtoM HCT (hazard ratio [HR] for OS, 1.91; P 5 .025; HR for NRM, 3.70; P 5 .0065). In FtoM HCT, patients with PBSCs frequently experienced fatal GVHD and organ failure. In conclusion, the use of PBSCs in FtoM HCT was associated with an increased risk of NRM in the early phase, resulting in inferior survival. This suggests that, when we use female-related donors for male patients in HCT, BM may result in better outcomes than PBSCs.