Re-infused Autologous Graft Natural Killer Cells Correlates with Absolute Lymphocyte Count Recovery after Autologous Stem Cell Transplantation

Abstract

Early absolute lymphocyte count (ALC) has been reported to be a powerful prognostic indicator of survival after autologous stem cell transplantation (ASCT). One possible source affecting ALC recovery includes the re-infused autologous graft lymphocytes (AGL). To assess if the re-infused AGL correlate with ALC recovery post-ASCT, we conducted a pilot study to identify which of the re-infused AGL subsets is most associated with day 15 ALC recovery in three patients with multiple myeloma and four patients with non-Hodgkin's lymphoma. Using the Spearman rank correlation coefficient analysis (r), we compared absolute numbers of CD3, CD4, CD8, CD19, and CD16+/CD56+ cells/kg of body weight from the apheresis product with ALC (cells/microl) at day 15 post-ASCT. The main lymphocyte subsets identified in the apheresis product were T cells and NK cells. There was no strong correlation between T or B cells from the apheresis product compared with the ALC at day 15 post-ASCT (CD3, r = 0.21; CD4, r = 0.32; CD8, r = 0.39; and CD19, r = 0.14). However, there was good correlation between NK cells from the apheresis product compared with ALC at day 15 post-ASCT (CD16+/CD56+/CD3-, r = 0.77). These data provide preliminary evidence that the number of re-infused autologous graft NK cells in the apheresis product significantly affect ALC recovery early post-ASCT. However, given the small sample size, our results are primarily hypothesis generating and subject of further research.

Importance of blood graft characteristics in auto-SCT: implications for optimizing mobilization regimens

“…38,40,41 Numbers of NK cells in the graft may be important to ensure rapid immune reconstitution. 42 Further, the number of CD8 þ cells in the graft seems to be important for early lymphocyte recovery. 43 There are currently insufficient data regarding the relation of graft CD34 þ cell content per se and immune recovery.…”

Mobilized peripheral blood grafts include more than hematopoietic stem cells: the immunological perspective

“…Lately, a more detailed characterization of graft immune cell subpopulations has been the subject of intense investigation; several studies [14][15][16][17] correlated higher number of T lymphocytes and NK cells infused within the graft with a clinical benefit in terms of speed of immune recovery and outcome after auto-SCT (Table 2).…”

Prognostic significance of early lymphocyte recovery after post-autografting administration of GM-CSF in non-Hodgkin's lymphoma

“…4,5 Recent data suggest that absolute NK cell subsets measured on day þ 15 post transplant and the kinetic of lymphocyte recovery, rather than its extent, are better prognostic indicators than the ALC measured on day 15. 4,17 Given the retrospective nature of this analysis, and the fact that peripheral blood lymphocyte subsets were not prospectively measured in this patient population, analysis of these factors could not be done.…”