Hi raunakgarg,
I doubt very many patients have used this therapy. Here is a peer-reviewed paper with more information about it:
EM Tyler and G Koehne, "The emergence of WT1-specific T-cell responses following allogeneic T cell-depleted hematopoietic stem cell transplantation and low-dose donor lymphocyte infusions is associated with a graft-vs.- myeloma effect," OncoImmunology, 2013 (full text of article)
Mark