Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for ATL with HTLV-1 Antibody-Positive Donors

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only available curative treatment option for patients with aggressive adult T cell leukemia-lymphoma (ATL). Donor human T cell leukemia virus (HTLV) 1 seropositivity is a critical concern when choosing relative donors, as they are not usually recommended due solely to the occurrence of donor-derived ATL. A previous report suggested that allo-HCT with an HTLV-1-seropositive donor increased ATL-related mortality. We updated the risk assessment for choosing an HTLV-1-seropositive allo-HCT donor for ATL. Our current registry data, which include larger numbers of HTLV-1-seropositive donors and longer observation periods, revealed no significant difference in overall survival (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.70-1.24; P = .61) or cumulative incidence of either ATL-related (HR, 0.96; 95% CI, 0.64 to 1.45; P = .80) or non-ATL-related mortality (HR, 0.91; 95% CI, 0.61 to 1.37; P = .66). Similarly, when considering only patients with ATL in complete remission, there was no significant difference in overall survival (HR, 1.02; 95% CI, 0.70 to 1.49; P = .91) or cumulative incidence of either ATL-related (HR, 1.20; 95% CI, 0.66 to 2.20; P=0.54) or non-ATL-related mortality (HR, 0.86; 95% CI, 0.52-1.42; P = .66). These data indicate that selecting HTLV-1-seropositive donors might not be contraindicated for patients with ATL receiving allo-HCT if alternative donors are unavailable. Further risk assessment remains to be performed.