Early and Long-Term Impaired T Lymphocyte Immune Reconstitution after Cord Blood Transplantation with Antithymocyte Globulin.

•We describe the different lymphocyte subsets kinetics (CD3+, CD4+, CD8+, CD19, and natural killer cells) after transplantation in umbilical cord blood recipients•We studied the predictive factors for each lymphocyte subset recovery after single umbilical cord blood transplantation in adult and pediatric patients•We report different factors that influenced lymphocyte subset recovery after cord blood transplantation: lower antithymocyte globulin dose, negative recipient cytomegalovirus serostatus, and younger patients•We describe the incidence and types of opportunistic infections in the different periods after cord blood transplantation•These results highlight the importance of optimizing the use of antithymocyte globulin in the conditioning regimen. Other factors, such as age and cytomegalovirus serostatus, also play a role that needs to be considered when designing new umbilical cord blood transplantation protocols to avoid infectious-related mortality