ABSTRACT
The first successful allogeneic hematopoietic stem cell transplantation (HSCT) was reported in 1968, when three children with congenital immunodeficiency diseases received bone marrow transplants (BMT) from human leukocyte antigens (HLA)-compatible healthy sibs (1,2). Pioneering studies of Dr. E. Donnall Thomas and colleagues, reported in the early 1970s, showed that BMT from HLA-matched sibs after high-dose chemotherapy and total body irradiation (TBI) could provide long-term, relapse-free survival in patients with refractory acute leukemia (3,4). Experience soon showed that better relapse-free survival occurred when the BMT was carried out in patients with first-or second-remission acute leukemia (5,6). In the late 1970s and early 1980s, allogeneic BMT was established as the only curative therapy for chronic myeloid leukemia (CML) (7). Initially, the vast majority of allogeneic HSCTs used HLA-identical sibling donors, but currently approximately 35% of all allogeneic HSCTs are carried out using unrelated volunteer donors identified through national or international registries. The first studies demonstrating the effectiveness of autologous HSCT in acute myeloid leukemia, Hodgkin’s disease, and non-Hodgkin’s lymphoma were reported in the mid-1980s (8-10). As a result of its widespread use for the treatment of breast cancer, autologous HSCT surpassed allogeneic HSCT in the mid-1990s, when breast cancer accounted for 40% of all autologous HSCTs (11). However, as the results of randomized trials showed no overall survival benefit in recipients of autologous HSCT for either early or advanced breast cancer (12), the number of autologous HSCTs for breast cancer has decreased significantly and now accounts for less than 5% of all autologous HSCT procedures. In contrast, several randomized trials since the mid-1990s have shown that high-dose therapy and autologous HSCT provide improved relapse-free survival in patients with multiple myeloma compared with conventional therapy (13). Consequently, 30% to 40% of all autologous HSCTs are now performed for multiple myeloma. The initial reports of allogeneic and autologous HSCT universally used bone marrow as the source of hematopoietic stem cells. By the early 1990s, the use of peripheral blood stem cells (PBSCs) for transplantation grew, especially in the autologous HSCT setting. Currently, more than 95% of all autologous HSCTs and more than 50% of allogeneic-related HSCTs are carried out using PBSCs.
