Use of granulocyte colony-stimulating factor for fluorine-18-fluorodeoxyglucose labeling in human leukocytes

Abstract

Objective Insufficient labeling efficiency and poor retention of radioactivity are the considerable shortcomings of fluorine-18-fluorodeoxyglucose (F-18-FDG) labeling in human leukocytes. This study was conducted to evaluate the feasibility of using granulocyte colony-stimulating factor (G-CSF) to improve F-18-FDG labeling in human leukocytes. Methods Leukocyte separation was performed using methods reported earlier. Separated leukocytes were preincubated with G-CSF or insulin at 37 degrees C for 1 h. After preincubation, labeling was performed with F-18-FDG (37-74 MBq) at 37 degrees C for 30 min. Retained radioactivity was assessed at 1-4 h after labeling by the same method described in earlier reports. The viability of labeled leukocytes was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Results Labeling efficiency of leukocytes preincubated with G-CSF, G-CSF with insulin, insulin, and control leukocytes was 52.1 +/- 8.9%, 49.9 +/- 10.5%, 40.3 +/- 7.7%, and 40.3 +/- 6.0%, respectively. G-CSF significantly increased the labeling efficiency compared with insulin (P=0.005) and control (P=0.004). In leukocytes preincubated with G-CSF, 77.0 +/- 1.2%, and 59.0 +/- 1.8% of radioactivity was retained at 1 and 3 h after labeling. There was no significan