Supplementary Material for: Haploidentical stem cell transplantation using post-transplant cyclophosphamide for T-cell prolymphocytic leukemia after alemtuzumab induction therapy: a case report

T-cell prolymphocytic leukemia (T-PLL) is a rare aggressive disease with a poor prognosis. Allogeneic stem cell transplantation (allo-SCT) followed by administration of alemtuzumab is the most promising treatment for T-PLL but is associated with a higher risk of infections since alemtuzumab strongly suppresses cellular immunity, leading to high transplant-related mortality and unsatisfactory survival. In addition, for patients without human leukocyte antigen-matched donors, haploidentical stem cell transplantation (haplo-SCT) using post-transplant cyclophosphamide (PTCy) has been used because of the ready availability of donors and results comparable to transplantation with human leukocyte-antigen matched donors. However, there are only a few reports on such transplantation for T-PLL, and the safety and efficacy of haplo-SCT after alemtuzumab therapy has remained unclear. Here, we describe a 66-year-old Japanese male patient with T-PLL treated successfully with haplo-SCT after induction therapy of alemtuzumab for T-PLL. About three months after the achievement of complete remission by alemtuzumab for T-PLL, haplo-SCT with reduced-intensity conditioning and PTCy was performed. Infectious complications were improved by early therapeutic interventions, and peripheral T cell counts gradually recovered. The patient has remained alive for more than 16 months after allo-SCT with no signs of relapse. Thus, haplo-SCT using PTCy should be considered as an option after alemtuzumab treatment for T-PLL.