Using related donors other than genotypically HLA-matched siblings in allogeneic hematopoietic stem cell transplantation for hematologic disease: a single institution experience in Japan.

Thirty patients with hematologic diseases received allogeneic hematopoietic stem cell transplants (HSCT) from related donors other than genotypically HLA-matched siblings. Their outcomes were compared with those of 102 patients who had received HSCT from genotypically HLA-matched siblings. All donors in the study group were HLA-haploidentical relatives, The degree of HLA mismatches in unshared haplotype was 0-locus (n = 6), 1-locus (n = 20), and 2-locus (n = 4). All patients in the study group achieved successful engraftment at a median of 17 days (range, 10-35 days). Grade II-IV and ITI-IV acute graft-versus-host disease (GVHD) occurred in 16 (53%) and 9 (30%) patients, respectively, in the study group, rates that were significantly higher than those of the control group, which were 33 (33%) and 12 (12%) patients, respectively (P = .034 and .022, respectively). The frequency of chronic GVHD was 85% (22 out of 26 evaluable patients) in the study group, a rate that was also significantly higher than that of the control group with 57% (52 of 91 patients) (P = .0078). The estimated probability of disease-free survival (DFS) for the study group was 56% at 5 years. When the 2 groups were compared according to the risk of disease, the probabilities of DFS at 5 years for patients with low risk in the study and for control groups were 100% and 84%, respectively, and those for patients with high risk were 43% and 42%, respectively. These results showed that the DFS for patients with both low and high risks in the study group was comparable to that of the control group. In conclusion, despite higher probabilities of acute and chronic GVHD, unmanipulated allogeneic HSCT from related donors other than genotypically HLA-matched siblings was considered to be a reasonable alternative for patients without genotypically HLA-matched sibling donors.