¹¹¹Indium Labelling of Human Washed Platelets; Kinetics and in Vivo Sequestration Sites

Abstract

The measurement of survival, tissue distribution and sites of destruction of human platelets is considered to be of some use to differentiate platelet disorders, to understand thrombosis and to evaluate the effects of drugs on platelets (1). The introduction of ¹¹¹1ndium (2) as a radioactive platelet label was a major improvement in comparison to the generally used ⁵¹Chromium (3).¹¹¹Indium is a gamma emitter with an energy favorable for external detection by a gamma camera. Furthermore, in the absence of transferrin, ¹¹¹lndium complexed to 8-hydroxyquinoline provides a very high efficiency labelling of about 80 to 90% (4). The labelling in nonplasmatic medium makes it necessary to wash platelets in conditions such that their discoid shape and their functions are not lost. Mustard’s technique for washing human platelets is known to fulfil these conditions (5). Joist and Thakur (4) demonstrated that rabbit platelets, washed with a similar technique and labelled with ¹¹¹1ndium-oxine remain non activated and survive normally when reinjected to the animals.