Blood diseases such as leukemia, aplastic anemia and congenial immunodeficiency were hard to treat in the past, but now, many patients can regain their health with bone marrow transplantation.

In order to carry out a successful transplantation, however, the patient's human leukocyte antigens (HLA) have to match the donor's . The odds of finding an HLA matching donor among the patient's siblings is 1 out of 4, but with non-relatives, it is 1 out of hundreds, even thousands or ten.

Consequently, quite a few patients requiring bone marrow transplantations never receive them. Thus, a marrow bank was started in 1992 to encourage volunteer donors nationwide to join the Marrow Donor Program. Many patients have been saved as a result. The number of patients requiring bone marrow transplantation in Japan is more than 1,000 a year. We now have roughly 90,000 registered volunteer donors. (as of, 12/1997) However, about 30% of these patients can't find an HLA matched donor, so more registered donors are required. We hope this booklet will help you to understand the importance of bone marrow transplantation and the marrow bank and will encourage you to register as a donor.