Impact of donor leukocyte telomere length and shortening post-alloHCT on outcomes in early-stage leukemia or myelodysplastic syndrome

Donor selection is a key success factor in allogeneic hematopoietic cell transplant (HCT). A multicenter study in the United States evaluated the potential impact of donor leukocyte telomere length (LTL) and LTL shortening in recipients at three months post HCT (LTL-3MS) on two-year HCT outcomes among patients undergoing HCT for early-stage leukemia or myelodysplastic syndrome (MDS). Among 384 HCT recipients a better 2-year overall survival was associated with longer donor LTL and higher LTL-3MS. Longer donor LTL was associated with a lower risk of non-relapse mortality, while higher LTL-3MS was associated with lower relapse risk. The adjusted 2-year cumulative risk of all-cause mortality was reduced by about half for patients with both donor LTL≥ 6.7 kb and LTL-3MS ≥ 230 bp compared with patients with neither characteristic (21% versus 41%; p<0.0001). The authors conclude that selection of donors with longer LTL may improve HCT outcomes, while limited LTL shortening in recipients post-HCT may guide relapse prediction.