Donor-specific anti-HLA antibodies predict outcome in double umbilical cord blood transplantation.

Using a uniform detection method for donor-specific anti-HLA antibodies (DSAs), we sought to determine the effect of preformed DSAs on outcomes in double umbilical cord blood transplantation. DSAs were associated with an increased incidence of graft failure (5.5% vs 18.2% vs 57.1% for none, single, or dual DSA positivity; P = .0001), prolongation of the time to neutrophil engraftment (21 vs 29 days for none vs any DSA; P = .04), and excess 100-day mortality or relapse (23.6% vs 36.4% vs 71.4% for none, single, or dual DSA positivity; P = .01). The intensity of DSA reactivity was correlated with graft failure (median of mean fluorescent intensity 17 650 vs 1 850; P = .039). There was inferior long-term progression-free and overall survival when comparing patients with DSAs against both umbilical cord blood units to those without DSAs (3-year progression-free survival, 0% vs 33.5%, P = .004; 3-year overall survival 0% vs 45.0%, P = .04). We conclude that identification of preformed DSAs in umbilical cord blood recipients should be performed and that the use of umbilical cord blood units where preformed host DSAs exist should be avoided.