The changes of serum leptin and soluble leptin receptor levels in patients undergoing mobilization of peripheral blood stem cells before autologous stem cells transplantation

Background and objectives: Leptin was demonstrated to stimulate the proliferation of hematopoietic stem cells in vitro, but there is scarce information concerning serum leptin levels in patients with hematological diseases. The aim of our study was to measure serum leptin levels in patients undergoing mobilization of peripheral blood stem cells (PBSC) before autologous stem cell transplantation (ASCT). Design and methods: Eighteen patients indicated for ASCT were included in the study The blood samples were obtained before the initiation of mobilization chemotherapy, at the phase of maximal leukopenia and on the second day of stem cell harvest. Serum leptin levels, soluble leptin receptor, cortisol, insulin, tumor necrosis factor alpha (TNFalpha), and interleukin-1 receptor antagonist (IL-1ra) levels were measured in the withdrawn samples. Results: The basal values of parameters measured except for higher levels of IL-1ra in mobilized group did not differ significantly from those of a control group of healthy subjects. Serum leptin levels decreased significantly at the leukopenia phase and remained suppressed in the stem cell harvest phase (means +/- standard error means (SEM): 12.2 +/- 2.4 vs. 7.7 +/- 1.5 vs. 9.3 +/- 1.9 ng mL(-1)). No significant changes were found in soluble leptin receptor, insulin, cortisol, and TNFalpha levels throughout three measurements, while IL-1ra levels increased significantly in the SC harvest phase compared to the previous two measurements. Interpretation and conclusions: As no metabolic variations explaining suppressed leptin levels were found, this suppression could be the result either of G-CSF administration or increased leptin consumption by activated stem cells.