Fatal immune-mediated pancytopenia and a TRALI-like syndrome associated with high titers of recipient-type antibodies against donor-derived peripheral blood cells after allogeneic bone marrow transplantation following dose reduced conditioning.

Pancytopenia occurring after bone marrow transplantation is a rare complication. A 47 year old patient with progression of multiple myeloma after standard therapy received an allogeneic marrow graft from a matched unrelated donor. The non-myeloablative conditioning regimen consisted of fludarabine, cyclophosphamide, rabbit anti-thymocyte globulin and total body irradiation. GVHD prophylaxis consisted of cyclosporine. Neutrophil engraftment was as expected and the patient was discharged without signs of acute GvHD. On day +34 the patient presented with clinical and laboratory findings consistent with severe pancytopenia. Antibodies against red cells, platelets, lymphocytes and granulocytes were detected in extremely high titers. Immune-mediated pancytopenia was refractory on multiple immunosuppressive treatment strategies. Proliferation of polyclonal plasma cells of recipient-type that was documented postmortem, was most likely responsible for excessive antibody formation.