Serum levels of stem cell factor in patients during transplantation of bone marrow or peripheral blood stem cells

Stem cell factor (SCF) synergizes with other cytokines in vitro to stimulat e the proliferation and differentiation of cells of the myeloid, megakaryoc ytic, erythroid, and lymphoid lineages. In vivo, it may play a role in engr aftment after transplantation of bone marrow (BM) or peripheral blood stem cells (PBSC), Serum levels of SCF were closely monitored in 82 patients bef ore and after allogeneic (n = 38), autologous (n = 6), or syngeneic (n = 1) BM transplantation (BMT) or autologous PBSC transplantation (PBSCT) (n = 3 7), respectively, SCF serum levels fluctuated around a mean in patients aft er allogeneic or autologous BMT or after PBSCT, In two patient subgroups (5 patients with acute myeloid leukemia [AML] and 6 patients with chronic mye logenous leukemia [CML]) with identical pretransplant conditioning regimen followed by allogeneic BMT, serum IL-6 levels significantly increased up to day +14 (p < 0.05). Correlation was not found between SCF serum levels and leukocyte or thrombocyte counts or the day of engraftment of these cell ty pes. These data are a basis for further studies and constitute a further mo saic stone in understanding the changes in the complex cytokine network dur ing engraftment.