Response to NK cell content does not seem to influence engraftment in ex vivo T cell depleted haploidentical stem cell transplantation
Abstract
In our recent publication in Stem Cell Reports (Lobo de Figueiredo-Pontes et al., 2021), we assessed the role of NK cells on hematopoietic stem cell (HSC) fate during HSC transplantation and concluded that NK cells, possibly via secretion of cytokines (and in particular IFNγ), negatively affect HSC frequency and function. In their letter in this issue of Stem Cell Reports, Merli and colleagues report carrying out an interesting attempt to translate our observations to clinics (Merli et al., 2022).
They performed a retrospective analysis of 2 cohorts of pediatric patients transplanted after ex vivo T cell depletion (Locatelli et al., 2017; Merli et al., 2021; Lang et al., 2014) and concluded that the amount of NK cells in the graft does not have an impact in the transplantation outcome. While we acknowledge the value of their analysis, we believe that there are critical factors between both studies that prevent Merli et al. from reaching our same conclusions.