Natural killer cell reconstitution after hematopoietic stem-cell transplantation in children.

Introduction: After hematopoietic stem cell transplantation (HSCT), natural killer (NK) cells reconstitution is the main barrier against viral infections.

Objective: To determine that the knowledge on the kinetics of NK cell reconstitution after HSCT contributes to transplant efficient monitoring, which increases the possibility of its success.

Method: Twenty-one patients undergoing HSCT were included, as well as a control group of clinically healthy individuals. At different time points after transplantation (range of 21 to 670 days), CD3- CD16+ CD56+ NK cells were quantified by flow cytometry in peripheral blood samples.

Results: NK cell recovery occurs at three to six months and 10 to 12 months post-transplantation; their number was significantly lower (in comparison with the control group) in the rest of the monitoring time.

Conclusions: The first period of NK cell recovery occurs between three and six months after transplantation. Reconstitution is transient and the number of NK cells varies in the first years.