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Marrow and hematopoietic cell transplants provide the possibility of a cure for patients with high risk and therapy-resistant leukemia. However the minority of patients are fortunate enough to have an HLA identical sibling. Transplants from HLA matched unrelated donors were of only theoretical interest given the very high degree of polymorphism among HLA antigens throughout the human population and the lack of organized groups of HLA-typed volunteer donors. Demonstration in the early 1980’s that unrelated marrow transplants were medically feasible gave great impetus to the creation of publicly supported donor registries (1-3). In the U.S., a national registry was authorized by congressional legislation in 1984, and in 1986 a federal contract initially administered by the Office of Naval Research was awarded to a consortium of investigators and centers headed by Dr. Jeffrey McCullough of the University of Minnesota (4). This consortium grew to become a comprehensive network of donor recruitment groups, donor centers, marrow and stem cell collection centers, and transplant centers known as the National Marrow Donor Program (NMDP). The NMDP currently consists of 96 donor centers and 127 transplant centers, including 8 donor centers located in countries outside the United States. National registries also exist in several other countries.

Various applications of therapeutically active cancer vaccines have recently been reviewed by Subiza et al. [1]. In their opinion, concepts and tools related to such therapies are more clear than ever before and clinical results are encouraging. Accompanying editorials express somewhat contrasting views. In one editorial the need is expressed for a combination of antigen-specific effect targeting the immune reaction to tumour plus a systemic immuno- or endocrine-modulating effect to treat cancer [2], and in the potential of the other producing progression or only temporary benefit following vaccine therapy [3].

The principal effects of interest with “high-level radiation” exposure (high doses and dose rates) are early “all-or-none” effects such as illness and death. These effects are due to the severe depletion of stem cell populations in the organs resulting from the high average absorbed organ doses (1). Absorbed organ dose-response curves for these all-or-none organ effects show the classic S-shape characteristic of such relationships well known in pharmacology, toxicology and medicine. The organ dose is the amount of energy per gram of tissue (100 ergs/gram), averaged usually over the entire organ.