Marrow Transplantation from Related Donors Other Than HLA-Identical Siblings

TLDR

Marrow transplantation has generally been limited to patients with a sibling who is genotypically identical for HLA. The study compared 105 hematologic cancer patients receiving marrow grafts from haploidentical donors with 728 similar patients receiving grafts from HLA‑identical siblings, noting that the donors’ unshared haplotypes varied from 12 phenotypically but not genotypically identical for HLA‑A, B, and D, to 6 differing at three loci. Study patients experienced higher rates of delayed engraftment, granulocytopenia, graft rejection, and earlier, more frequent acute graft‑versus‑host disease, yet survival did not differ significantly from controls, and the risk did not correlate with Class I versus Class II locus disparity. Published in N Engl J Med 1985; 313:765–71.

Abstract

Marrow transplantation has generally been limited to patients with a sibling who is genotypically identical for HLA. In a study of the acceptable limits of HLA incompatibility, 105 consecutive patients with hematologic cancers who received marrow grafts from haploidentical donors (study group) were compared with 728 similar patients concurrently receiving grafts from HLA genotypically identical siblings (control group). The unshared haplotypes differed variably: 12 were phenotypically but not genotypically identical for HLA-A, HLA-B, and HLA-D; 63 differed at one locus (A, B, or D); 24 at two loci; and 6 at three. A higher proportion of study patients had delayed engraftment, granulocytopenia, or graft rejection. Acute graft versus host disease occurred earlier and with greater frequency in study patients. The risk of the disease did not correlate with disparity for Class I (A or B) versus Class II (D-region) loci. Thus, incompatibility for HLA has an important effect on the course after clinical marrow transplantation. In spite of these complications, there was no statistically significant difference in the survival of the study patients and control patients who received their transplants during remission. (N Engl J Med 1985; 313:765–71.)