“…Following the initial successful application of HLAcompatible bone marrow transplantation for the treat ment of severe combined immunodeficiency (SCID) [1] and Wiskott-Aldrich syndrome [2] in 1968, transplants of HLA-identical marrow rapidly emerged as a potentially curative treatment of choice for several lethal, congenital disorders of the immune system, including the following: various forms of SCID [3][4][5], Nezelof s syndrome [6][7][8], bare lymphocyte syndrome [9], reticular dysgenesis [10], cartilage-hair hypoplasia syndrome [11,12], WiskottAldrich syndrome [13][14][15], and the Chédiak-Higashi syn drome [16]. Results of transplants for these and other congenital disorders have recently been reviewed [17], Unfortunately, normal HLA-identical sibling donors are available for only about 40% of cases.…”