Histocompatibility and bone marrow transplantation (BMT).

Possible donors may be recommended by the following order: 1. HLA-identical twins (syngeneic) 2. HLA-identical siblings 3. HLA-haploidentical related donors The increased number of additional HLA-incompatibilities (HLA-A, -B, -DR) increases the risk of GVHD. 4. HLA-phenoidentical and MLC-negative unrelated donors The DRS for BMT includes the early HLA typing of the patient and of all related potential donors, covering all known antigens. Evidence on the basis of MLC should be available for cellular non-reactivity between donor and recipient cells, although this will be rarely possible with haploidentical related donors. Donor-specific HLA antibodies must not be detectable in the recipient. No generally accepted method has so far become available for consideration of minor histocompatibility antigens in the context of DRS for BMT.