F-18-FDG labelling of human leukocytes

Radiolabelled leukocytes are useful for the imaging of inflammation and inf ection, and F-18- fluorodeoxyglucose (F-18-FDG) is known to concentrate in metabolically active cells. We evaluated the feasibility of leukocyte label ling with F-18-FDG using ACD and heparin anticoagulants at 20 degrees C and 37 degrees C, with and without gentle mixing during incubation. With leuko cytes (WBC) harvested from 20 mi blood, studies were performed using F-18-F DG in concentrations of 3.7-74 MBq (0.1-2.0 mCi). F-18-FDG WBC stability in platelet-poor plasma was assessed at 1-4 h. Satisfactory labelling efficie ncy was achieved with incubation in heparin-saline at 37 degrees C for 30 m in (62.7+/-1.6%), and was further enhanced by mixing during incubation (78. 1+/-3.9%). Cell labelling was predominantly of granulocytes (78.5 +/- 1.4%) . F-18-FDG WBC was relatively stable in platelet-poor plasma for up to 4 h, and no cell staining was observed in viability studies using trypan blue. These results indicate the feasibility of leukocyte labelling with F-18-FDG , providing an approach that may be useful in PET imaging of inflammation a nd infection. ((C) 2000 Lippincott Williams & Wilkins).