Allogeneic graft CD34+ cell dose correlates with dendritic cell dose and clinical outcome, but not with dendritic cell reconstitution after transplant

Objective This study examined whether the CD34+ cell dose in allografts correlates with the dose of myeloid dendritic cells (mDC) and plasmacytoid DC (pDC), and with DC reconstitution and clinical outcome after a myeloablative HLA-matched transplant. Patients and methods Fifty-three patients were included in this study: 37 who had undergone a granulocyte colony-stimulating factor mobilized peripheral blood stem cells (PBSC) transplant from related donors and 16 who had undergone a marrow transplant from unrelated donors. The number of CD34+ cells, lin−HLA-DR+CD11c+ mDC, lin−HLA-DR+CD123+ pDC, CD14+ monocytes, and CD3+CD4+, CD3+CD8+, CD56+, and CD19+ lymphocytes was compared in the graft, as well as in the peripheral blood after transplant, in patients receiving more than versus less than or equal to the median number of CD34+ cells in PBSC (5.78×106/kg) or in marrow (2.8×106/kg). Results A higher CD34+ cell dose was associated with larger numbers of mDC in PBSC (p = 0.01) and pDC in marrow grafts (p = 0.004). However, neither mDC nor pDC recovery after transplant correlated with the number of CD34+ cells infused. Finally, higher doses of CD34+ cells appeared to negatively affect (p = 0.02) the overall survival in PBSC transplantation and were associated with a trend for higher acute graft-vs-host disease in PBSC and lower acute graft-vs-host disease in marrow transplant. Conclusions CD34+ cell dose correlates with the dose of different DC subsets in PBSC and marrow grafts, but it does not affect DC reconstitution after transplant. Higher doses of CD34+ cells in PBSC, but not in marrow, seem to adversely affect survival after transplant.