The outcome and characteristics of patients with relapsed adult T cell leukemia/lymphoma after allogeneic hematopoietic stem cell transplantation.

Treatment options for patients with adult T cell leukemia/lymphoma (ATLL) who have relapsed disease after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are limited. To clarify which patients with ATLL are likely to benefit from these treatment options and to define patient populations for novel treatments, we performed a nationwide retrospective analysis of 252 Japanese patients who had relapsed ATLL after allo-HSCT. Some long-term survivors remained after tapering and withdrawal of immunosuppressive agents. Thirty-six patients who received donor lymphocyte infusion had a better overall survival (OS) in comparison to those who did not [hazard ratio (HR), 0.63; 95% confidence interval (CI), 0.43-0.93; P = .02], suggesting the efficacy of a graft-versus-ATLL (GvATLL) effect even after relapse. Multivariate analysis demonstrated that skin lesions at initial relapse of ATLL were independently associated with higher OS (HR, 0.41; 95% CI, 0.22-0.74; P = .003), indicating that the skin is a susceptible target organ of GvATLL. This study suggested that enhancement of a GvATLL effect is a potential therapeutic option for relapsed disease after allo-HSCT. Further investigations of incorporation of immune-based approaches with new molecular target drugs into the therapeutic options of patients with ATLL before and after transplantation are warranted.