The Prognostic Importance of Pre and Post Dendritic Cells in Autologous Transplantation for Diffuse Large B Cell Lymphoma.

Pre and post transplant dendritic cell (DC) levels may correlate with survival, GVHD, and relapse in allogeneic BMT. Whether they have prognostic importance in autologous peripheral blood progenitor cell (PBPC) is unknown. We prospectively collected pre and post dendritic cell levels, including DC1 and DC2 levels in 53 patients with diffuse large B cell lymphoma (DLBCL) to investigate their potential prognostic importance. Pre-transplant analysis of DC1 and DC2 by flow cytometry was obtained 24 hours prior to the initiation of VP-16 (2 gm/m²) or G-CSF (10 mcg/kg/d) (n=4) for PBPC mobilization; post transplant samples were obtained 6 weeks after transplant. 51 of 53 (96%) were sensitive to chemotherapy at the time of transplant; 34% received prior radiation therapy; 15% had an elevated LDH at transplant. 49 of 53 received VP-16 + G-CSF for stem cell mobilization and 4 patients received G-CSF alone. 98% received a preparative regimen of Bu/Cy/VP and one patient received Busulfan alone. In a univariate analysis, higher numbers of pre-transplant DC1 cells and pre-transplant total DC (DC1 + DC2) cells correlated with improved survival, as shown graphically below:

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Patients received a median CD34+ cell dose of 8.7 x 10⁶/kg. DC values did not correlate with CD34+ cell yield. Post-transplant DC1 (p=0.03), DC2 (p=0.035), and post-transplant total DCs (p=0.04) also correlated with improved survival. In all cases, more DCs was associated with a better outcome. In a multivariable model, pre-transplant total DC number (p=0.028), and a normal LDH at the time of transplant (p=0.017) correlated with improved outcome. Median follow up of surviving patients is 15 months. Of 26 patients with pre-transplant total DC numbers greater than 9.10 x 10⁶/mL, 77% of patients are alive, as compared to 56% of patients with pre-transplant total DC numbers less than 9.10 x 10⁶/mL (n= 27)(p=0.022). The high DC group had fewer relapses and fewer late infections. We conclude that higher pre-transplant total DC numbers are associated with improved outcome in ABMT for DLBCL.