Introduction

Recent progress in the treatment of aplastic anemia has dramatically changed the previously grim prognosis for these patients, so that today the 2-year survival is 60–90% (Bacigalupo et al., 1988, 1995; Camitta and Doney, 1990; Doney et al., 1997; Gluckman et al., 1992a,b; Paquette et al., 1995; Passweg et al., 1997; Young, 1994). Improved results following bone marrow transplantation or immunosuppression increase the number of long-term survivors so that immediate survival is no longer the sole concern. Indeed, quality of life and late complications are becoming increasingly important (Deeg, 1990a,b; Duell et al., 1997; Kolb and Bender–Gotze, 1990). However, there are basic differences between both treatment modalities, resulting in their having specific effects on late morbidity and long-term survival.

Patients are likely to be cured of aplastic anemia by successful marrow transplantation. Late effects are caused by the treatment used to prepare the patient for transplantation, and the extent of chronic graft-versus-host disease and its treatment rather than the underlying disease. In contrast, after immunosuppression recovery often takes several months and stigmata of the disease persist despite clinical remission (Marsh et al., 1990, 1991; Nissen et al., 1980, 1993; Rudivic et al., 1985). Although immunosuppression allows autologous reconstitution of hemopoiesis, it leaves the patient with a fragile bone marrow prone to the development of a clonal disorder, such as myelodysplastic syndrome (MDS) or paroxysmal nocturnal hemoglobinuria (PNH).