Audit of peripheral stem cell transplantation for aplastic anemia in multitransfused infected patients

Allogeneic hematopoietic stem cell transplantation is a curative modality for aplastic anemia; the preferred stem cell source is bone marrow. However, allogeneic peripheral blood stem cell transplantation (PBSCT) used in high-risk patients is associated with higher risk of chronic graft-versus-host disease (GVHD). Our center receives multitransfused, alloimmunized, infected, late referrals for transplant.

Forty-one patients of median age 22 years (range 8-37) received allogeneic-PBSCT from human leukocyte antigen (HLA)-matched sibling donors. The median time since diagnosis was 12 months (range 4-65) and median pretransplant transfusions were 37 (range 6-160). Six patients were platelet refractory and one alloimmunized for pan-red blood cell (RBC) antigens. Several patients had pretransplant icterus or renal dysfunction and 26 (63.4%) had unresponsive bacterial/fungal infections. Our conditioning regimen included fludarabine 30 mg/m(2) for 6 days (days -10 to -5), cyclophosphamide 60 mg/kg/d for 2 days (days -6 to -5), and antithymocyte globulin (ATGAM) 30 mg/kg/d for 4 days (day -4 to -1), which was reduced to 2 days in 2 patients. We used standard GVHD prophylaxis with cyclosporine and methotrexate on days 1, 3, 6, 11.

The median follow-up period was 29 months (range 6-78) and median engraftment time 10 days (range 8-17). Thirty-one patients (75.6%) were treated for infections, with 20 of these on antifungals for preexisting infections. There were two graft rejections and 10 (24.4%) deaths, with three intracranial hemorrhages, two rejections with infection, three cases of refractory GVHD (acute/overlap syndrome) with cytomegalovirus reactivation, and two invasive fungal infections. Overall incidence of acute GVHD was 39% with 2 grade IV cases. Ten (25%) cases developed chronic GVHD, with extensive GVHD in four.

With more experience using shortened course of ATGAM, HLA-matched donor transfusions, and availability of newer antifungals, we have been able to decrease PBSCT-related mortality. Further improvement will be possible with early referrals.