Introduction

Severe acquired aplastic anemia (SAA) is the first disease for which HLA-identical sibling bone marrow transplantation (ID-BMT) has been shown by a prospective study to be the preferred treatment (Camitta et al., 1976). In contrast the role of alternative donor BMT in the treatment of the 60–70% of patients with SAA who lack an HLA-identical sibling is not yet established. In this chapter we first briefly review factors that influence the outcome of ID-BMT. Secondly, we review published results of alternative donor BMT, highlighting major problems. Finally we present the results of an analysis of data from the International Bone Marrow Transplant Registry (IBMTR), the European Bone Marrow Transplant Group (EBMT) SAA Working Party, the Fred Hutchinson Cancer Research Center (FHCRC), and the International Marrow Unrelated Search and Transplant (IMUST) Study. From these data we make tentative recommendations for patient, donor and protocol selection for alternative donor BMT for SAA.

Prognostic factors for HLA-identical sibling BMT

ID-BMT results in a 90% probability of the long-term survival of minimally transfused patients (Storb et al., 1980). The probability of graft failure after ID-BMT increases with the number of pretransplant transfusions (Champlin et al., 1989).