Effect of AMD3100 on T Lymphocyte Subpopulations in Apheresis Products of Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation for Non Hodgkin Lymphoma.

AMD3100, a CXCR4 receptor antagonist, has been studied as a stem cell mobilization agent for the purpose of autologous stem cell transplantation (ASCT) in hematologic malignancies. Lymphocyte subset analysis of peripheral blood in patients treated with AMD3100 has been studied in healthy volunteers. To date, no reports exist describing the lymphocyte subsets of the autograft in patients undergoing AMD3100 stem cell mobilization for the purposes of ASCT in non-Hodgkin lymphoma (NHL). Considering our prior work demonstrating the significant impact of autograft lymphocyte content on clinical outcomes of patients undergoing ASCT for NHL we set out to profile autograft lymphocyte subsets of patients undergoing mobilization with AMD3100. Using flow cytometry, we analyzed aliquots of apheresis products in 7 patients with NHL undergoing AHSCT who received AMD3100 in addition to G-CSF as a part of their mobilization regimen. These results were compared to 29 patients with NHL who had undergone stem cell mobilization with G-CSF alone. There were no significant differences between these two groups of patients in terms of sex, age, performance status, histology, LDH, and number of pretransplant chemotherapeutic regimens. CD34+ cells collected at apheresis did not differ significantly between the groups. However, compared with G-CSF alone, patients that received AMD3100 had an approximate 5-fold increase in CD4+ cells (0.62 x 10⁹ cells/kg vs. 0.12 x 10⁹ cells/kg, p = 0.0004), a 3.5-fold increase in the absolute number of autograft CD3+ cells (1.21 x 10⁹ cells/kg vs. 0.33 x 10⁹ cells/kg, p = 0.0017), and a 2.5-fold increase in CD8+ cells (0.48 x 10⁹ cells/kg vs 0.19 x 10⁹ cells/kg, p = 0.215). A significant increase was also noted in CD4+25+ cell compartment (0.17 x 10⁹ cells/kg vs. 0.006 x 10⁹ cells/kg, p = 0.0001). No significant difference was noted in the absolute number of autograft CD16+56+ NK cells. Finally, an increase in the autograft total absolute lymphocyte count (41.6 x 10⁹ cells/kg vs. 2.88 x 10⁹ cells/kg, p < 0.001) as well as peripheral blood absolute lymphocyte count at day 15 after AHSCT was observed in those patients who had received AMD3100 (0.79 x 10⁹ cells/kg vs. 0.58 x 10⁹ cells/kg, p = 0.04). The increased lymphocyte content of the autograft (total and subset) would suggest the potential of positive impact on clinical outcomes in patients mobilized with AMD3100. Indeed, none of the patients who received AMD3100 had relapsed disease at one year post-transplant (although two of these patients are currently 9 months and 11 months post-transplant respectively), whereas 10 of the 29 control patients had relapsed disease at one year. Further studies are necessary to confirm these observations and ascertain their clinical significance.