Successful treatment of pure red cell aplasia with a single low dose of rituximab in two patients after major ABO incompatible peripheral blood allogeneic stem cell transplantation.

Dear Sir, Pure red cell aplasia (PRCA) occurs in 10–20% patients who underwent ABO-incompatible allogeneic haematopoietic stem cell transplantation (allo-HSCT). The mechanism for PRCA has been presumed to be persistence of recipient isohaemagglutinins, produced by residual host B lymphocytes or plasma cells, which are directed against donor erythroid progenitors (Sahovic et al., 1991). However, optimal treatment of PRCA after HSCT is not well established. Rituximab is a chimeric IgG1 monoclonal antibody directed against the CD20 surface antigen expressed by most human B lymphocytes and may eradicate B cells in vivo (Carton et al., 2004). Here, we report two patients with PRCA after ABO incompatible allogeneic peripheral blood stem cell transplantation (PBSCT) successfully treated with a single low dose of rituximab.