@article{Petersdorf_Gooley_Volt_Kenzey_Madrigal_McKallor_Querol_Rafii_Rocha_Tamouza_Chabannon_Ruggeri_Gluckman_2021, place={Pavia, Italy}, title={Use of the HLA-B leader to optimize cord blood transplantation}, volume={106}, url={https://haematologica.org/article/view/haematol.2020.264424}, DOI={10.3324/haematol.2020.264424}, abstractNote={<p>Cord blood transplantation (CBT) can cure life-threatening blood disorders. The HLA-B leader affects the success of unrelated donor transplantation but its role in CBT is unknown. We tested the hypothesis that the HLA-B leader influences CBT outcomes in unrelated single-unit cord blood transplants performed by Eurocord/European Blood and Marrow Transplant (EBMT) centers between 1990 and 2018 with data reported to Eurocord. Among 4,822 transplants, 2,178 had one HLA-B mismatch of which 1,013 were HLAA and HLA-A and -DRB1 matched. The leader (methionine [M] or threonine [T]) was determined for each HLA-B allele in patients and units to define the genotype. Among single HLA-B-mismatched transplants, the patient/unit mismatched alleles were defined as leader-matched if they encoded the same leader, or leader-mismatched if they encoded different leaders; the leader encoded by the matched (shared) allele was determined. The risks of graft-versus-host disease, relapse, non-relapse mortality and overall mortality were estimated for various leader-defined groups using multi-variable regression models. Among the 1,013 HLA-A and -DRB1-matched transplants with one HLA-B mismatch, increasing numbers of cord blood unit M-leader alleles was associated with increased risk of relapse (hazard ratio [HR] for each increase in one Mleader allele 1.30, 95% Confidence Interval [CI]: 1.05-1.60, P=0.02). Furthermore, leader mismatching together with an M-leader of the shared HLA-B allele lowered non-relapse mortality (HR 0.44, 95% CI: 0.23-0.81; P=0.009) relative to leader matching and a shared T-leader allele. The HLA-B leader may inform relapse and non-relapse mortality risk after CBT. Future patients might benefit from the appropriate selection of units that consider the leader.</p&gt;}, number={12}, journal={Haematologica}, author={Petersdorf, Effie W. and Gooley, Ted and Volt, Fernanda and Kenzey, Chantal and Madrigal, Alejandro and McKallor, Caroline and Querol, Sergio and Rafii, Hanadi and Rocha, Vanderson and Tamouza, Ryad and Chabannon, Christian and Ruggeri, Annalisa and Gluckman, Eliane}, year={2021}, month={Dec.}, pages={3107-3114} }