Five leucocyte labelling techniques: a comparative in-vitro study

Abstract

During the past years, several authors have used labeled leukocyte to detect inflammatory foci. However, before routine use in man, it is necessary to control the viability of labeled cells. Five leukocyte labeling techniques (111In-oxine, 111In-oxine without extraction, 99mTc-oxine, pyrophosphate 99mTc, 51Cr) were compared using the same separation methods, conservation medium, viability assays and migration studies. EM studies allowed the assessment of cellular damage induced by the labeling techniques as well as the calculation of the percentage of cells disrupted during preparation. Results obtained in vitro using 111In-oxine were not satisfactory and appeared contradictory to those published by the authors using this technique in vivo. Even the best method, pyrophosphate 99mTc labeling, was not completely atoxic, but the functional behavior of the leukocytes did not seem affected. While in vitro studies offer much information concerning labeled cells, they cannot predict the in vivo behavior of these cells.