Impact of the source of hematopoietic stem cells on immune reconstitution after transplantation: A systematic review.

Hematopoietic stem cell (HSC) transplantation's success lies in its ability to induce immune reconstitution. To date, there is no review published to compare the immune reconstitution among the three sources of HSC: umbilical cord blood (UCB), bone marrow (BM), and peripheral blood (PB). The review aims to analyze the kinetic of immune reconstitution among UCB, PB, and BM in HSC transplant patients by focusing on natural killer (NK) cells, B and T lymphocytes, and neutrophils. A systematic review was conducted through five databases, searching for clinical trials and randomized control trials (RCTs) which analyze the kinetics of immune reconstitution in at least two sources. Selected studies were assessed with Cochrane RoB 2.0. This review included 14 studies, with a total of 2539 subjects. The PB group achieved the fastest time to neutrophil recovery, while the B-cell count was the highest in the UCB group. The T-cell count is the lowest in the BM group, and the NK-cell count does not differ significantly among the three HSC sources. Among the three sources of HSC, there is no superior HSC source for any immune reconstitution parameter. More studies must be conducted to compare the immune reconstitution and clinical outcomes of all HSC sources in specific diseases.