HLA-mismatched haploidentical transplantation using low-dose alemtuzumab

Abstract

 Alemtuzumab is a monoclonal antibody against CD52, which is expressed on pan-lymphocytes. It has a long terminal half-life after it has been added to conditioning regimens. Therefore, it can prevent graft rejection and graft-versus-host disease (GVHD) by depleting host and donor T-cells, respectively. Previous clinical trials have shown that human leukocyte antigen (HLA)-mismatched haploidentical transplantation using alemtuzumab could be performed safely, although prophylaxis against viral infection should be considered carefully. On the other hand, a high relapse/progression rate was still observed in non-remission patients, even in the present trials, which included lower doses of alemtuzumab and methotrexate and rapid tapering of cyclosporine. We are now planning to perform prophylactic donor lymphocyte infusion after haploidentical transplantation to augment the graft-versus-tumor effect.