The influence of automated plateletpheresis on systemic levels of hematopoietic growth factors

BACKGROUND: Megakaryocytopoiesis and platelet production are regulated by s everal hematopoietic growth factors. The present study focuses on the effec ts of automated plateletpheresis on systemic levels of different hematopoie tic growth factors. STUDY DESIGN AND METHODS: Platelet count, mean platelet volume, and serum l evels of thrombopoietin, erythropoietin, interleukin-1 beta, interleukin-6, and stem cell factor in 21 healthy donors were measured before platelet co llection, after the first half of the apheresis procedure, at the end of ap heresis, and on Days 1, 2, and 7 thereafter. RESULTS: Thrombopoietin levels (initial level: 49.5 +/- 25.5 pg/mL) showed a significant increase between measurements taken at the end of apheresis a nd Day 1 (56.9 +/- 26.7 pg/mL; p = 0.01). There was a highly significant de crease in stem cell factor levels during apheresis (p < 0.0005), reaching p reapheresis values (1679 +/- 210 pg/mL) on Day 1. A highly significant incr ease in erythropoietin levels (initial level: 7.5 +/- 4.0 U/L) was seen aft er apheresis (p < 0.0005 on Days 1 and 2).The level remained significantly elevated until Day 7 (p = 0.004). Interleukin-1 beta and interieukin-6 leve ls (before donation: 1.4 +/- 1.8 pg/mL and 1.1 +/- 0.7 pg/mL, respectively) did hot change during the observation period. Thrombopoietin levels correl ated consistently and inversely with stem cell factor levels after apheresi s (Day 1, r = -0.46, p = 0.035; Day 2, r = -0.50, p = 0.02; Day 7, r = -0.5 0, p = 0.02). CONCLUSION: The data show a coordinated response of the hematopoietic syste m to platelet loss. It is suggested that the decrease in serum stem cell fa ctor levels during apheresis reflects the consumption of stem cell factor b y early hematopoietic progenitors that expand to initiate early megakaryocy topoiesis. The temporary increase in thrombopoietin is the result of platel et loss and serves as a stimulus for subsequent thrombopoiesis. The pronoun ced elevation of erythropoietin after apheresis suggests a role for this pr imarily erythropoietic cytokine in thrombopoiesis, too.