Comparison of chemotaxis and superoxide generation of indium-111-oxine- and technetium-99m-HMPAO-labelled granulocytes

Abstract

The diagnostic value of imaging infection with labelled granulocytes depends on the functional integrity of the reinfused cells. The aim of this study was to compare the functional integrity of granulocytes labelled with indium-111-oxine and technetium-99m-hexamethylpropyleneamineoxime (HMPAO), respectively, in comparison to unlabelled control granulocytes. Granulocytes were purified from healthy subjects and labelled with either ¹¹¹In-oxine or ^99mTc-HMPAO. Chemotaxis and superoxide production induced by formyl-peptide and phorbol-myristate-acetate were measured. Granulocytes labelled with ¹¹¹In-oxine had significantly (p<0.001) decreased chemotaxis. Superoxide production of granulocytes stimulated with phorbol-myristate-acetate showed no significant difference between control cells and those labelled using either technique. In contrast, formyl-peptide-stimulated superoxide production was increased in granulocytes labelled with ¹¹¹In-oxine (p<0.01) and in cells labelled with ^99mTc-HMPAO (p<0.03), indicating a priming compared to unlabelled cells. In conclusion, ^99mTc-HMPAO-labelled granulocytes show biological properties superior to ¹¹¹In-oxine-labelled cells, and should therefore be favoured for use in leucocyte labelling and infectious disease imaging.

Key Words:

• leucocyte scintigram
• phagocyte function
• granulocyte defect