Determination of polymorphonuclear neutrophil adhesion receptors: Influence of pre-analytic factors.

Polymorphonuclear neutrophil (PMN) adherence receptors expression varies wi th leukocyte activation state. Their quantification need accurate and inter -laboratories reproducible methods, without artefactual activation. Objective : The aim of this study was to study the influence of cell prepar ation on PMN adherence receptors expression. Materials and methods: It was proposed to quantify, using immunolabeling st andard (QIFIKIT(R), Dako), surface expression of the main adherence recepto rs (L-selectin and beta(2) integrins), from different preparations of PMN: total blood collected with EDTA, isolated PMN by density gradient Polymorph prep(TM) 1,113 (Nycomed Pharma) and formaldehyde fixed PMN. Results : A decrease of all receptors was noted after isolation and fixatio n of PMN, in comparison with whole blood PMN analysis. These results differ ed from data previously reported since, in these studies, activated phenoty pes (increased of beta(2) integrins) were observed after isolation and fixa tion methods. Conclusion: The present study provides strong evidence that pre-analytical conditions are sources of biological variations and thus extreme care must be taken in the interpretation of results. It underlines the interest of co nsensual practices for these pre-analytic and analytic parameters in order to compare results in multicenter and longitudinal studies.