Serum soluble IL-6 receptor levels during the mobilization of stem cells to peripheral blood.
Serum soluble interleukin-6 receptors (sIL-6R) have been demonstrated to play an important role in hematopoiesis. We report here that serum sIL-6R levels reflect proliferative kinetics of the progenitors after stimulation by chemotherapy plus granulocyte colony-stimulating factor. Serum sIL-6R were serially evaluated in 26 courses of peripheral blood (PB) stem cell collections in 16 patients using enzyme-linked immunosorbent assay. Expressions of IL-6R and CD34 on PB mononuclear cells were examined by flow cytometric analysis and expressions of IL-6R mRNA were examined by reverse transcriptase polymerase chain reaction. There were no significant differences between the serum sIL-6R levels on day 0 in patients (27.8+/-2.1 ng/ml, mean +/- SEM) and those in controls (27.5+/-1.5 ng/ml). Following chemotherapy the serum sIL-6R levels were significantly decreased, reaching a minimal level on day 14 (22.3+/-1.2 ng/ml, p < 0.01) and then significantly increased to above the baseline levels on day 21 (32.0+/-2.1 ng/ml, p < 0.01). Similar oscillations in the number of white blood cells, IL6R+ cells, CD34+ cells and colony-forming unit-granulocyte/macrophage (CFU-GM) in PB could be observed and the peak expression of mRNA was compatible with the expression of antigen. Serum sIL-6R levels on day 17 and 19 were positively correlated with the number of CD34+ cells, IL-6R+ cells, CFU-GM in PB and the number of collected CD34+ cells in leukapheresis products. In addition, when comparing the 2 groups divided by the number of prior chemotherapies, the status of disease or dose of the mobilizing regimen, the serum sIL-6R levels were significantly increased after day 17 in the group that received fewer courses of prior chemotherapy, the group in complete remission and the group of high-dose chemotherapy. These findings indicated that sIL-6R levels do not reflect the hematopoietic ability in the steady state, or the capability of the hematopoiesis after stimulation. Thus, sIL-6R levels may be a marker for the timing of PBSC collection or the prediction of the number of collected CD34+ cells.
Omura
Hiromi
H
Second Department of Internal Medicine, Faculty of Medicine, Tottori University, Japan. omura@grape.med.tottori-u.ac.jp
Kawatani
Toshio
T
Tajima
Fumihito
F
Ishiga
Kiyomi
K
Ohmura
Hiroshi
H
Kawasaki
Hironaka
H
Nanba
Eiji
E
D000328:Adult; D018952:Antigens, CD34 / Q000032:analysis; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000494:pharmacology; D015415:Biomarkers / Q000097:blood; D005260:Female; D019337:Hematologic Neoplasms / Q000097:blood / Q000628:therapy; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D007937:Leukapheresis / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000097:blood; D019947:Receptors, Interleukin-6 / Q000097:blood* / Q000235:genetics / Q000502:physiology; D012995:Solubility
D018952:Antigens, CD34; D015415:Biomarkers; D012333:RNA, Messenger; D019947:Receptors, Interleukin-6