COMPARISON OF CHEMOTAXIS AND SUPEROXIDE GENERATION OF INDIUM-111-OXINE-LABELED AND TECHNETIUM-99M-HMPAO-LABELED GRANULOCYTES

The diagnostic value of imaging infection with labelled granulocytes d epends on the functional integrity of the reinfused cells. The aim of this study was to compare the functional integrity of granulocytes lab elled with indium-111-oxine and technetium-99m-hexamethylpropyleneamin eoxime (HMPAO), respectively, in comparison to unlabelled control gran ulocytes. Granulocytes were purified from healthy subjects and labelle d with either In-111-oxine or Tc-99m-HMPAO. Chemotaxis and superoxide production induced by formyl-peptide and phorbol-myristate-acetate wer e measured. Granulocytes labelled with In-111-oxine had significantly (p<0.001) decreased chemotaxis. Superoxide production of granulocytes stimulated with phorbol-myristate-acetate showed no significant differ ence between control cells and those labelled using either technique. In contrast, formyl-peptide-stimulated superoxide production was incre ased in granulocytes labelled with In-111-oxine (p<0.01) and in cells labelled with Tc-99m-HMPAO (p<0.03), indicating a priming compared to unlabelled cells. In conclusion, Tc-99m-HMPAO-labelled granulocytes sh ow biological properties superior to In-111-oxine-labelled cells, and should therefore be favoured for use in leucocyte labelling and infect ious disease imaging.