WT1 and plasma cell myeloma: Moreover, WT1-specific T-cell responses have been reported in a series of relapsed MM patients undergoing allogeneic hematopoietic stem cell transplant (allo-HSCT), demonstrating a clear correlation between the emergence of such WT1-specific cytotoxic T lymphocytes (CTLs) and the graft-versus-myeloma effect, particularly in patients treated with donor lymphocyte infusions (DLIs) [20].