Upregulation of granulocyte CD11b (CR 3) after labelling with technetium-99m hexamethylpropylene amine oxime.

Today technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) is widely used for leucocyte scintigraphy, as 99mTc-HMPAO selectively labels granulocytes in mixed leucocyte suspensions. However, the influence of cell labelling on the expression of specific adhesion proteins has not been studied before. Therefore, we investigated five patients, four of whom had established Crohn's disease. We found that leucocyte labelling with 99mTc-HMPAO induces increased expression of the glucoprotein receptor CD11b on granulocytes, but it is not clear whether this upregulation affects the functional integrity of the granulocytes.