On the detection of neutrophil-derived vascular endothelial growth factor (VEGF).

In recent years, several investigators have addressed the question of whether mature polymorphonuclear neutrophils (PMN) are able to secrete cytokines. Their studies have brought forward new and exciting discoveries, by establishing that the release of inflammatory cytokines constitutes a novel and important aspect of the neutrophil biology, thereby emphasizing that PMN should no longer be regarded as cells that only release preformed mediators. Although it is still premature to assess the true biological significance of cytokine production by neutrophils, this new aspect of neutrophil biology opens novel perspectives as to the potential role of these cells in the inflammatory and immune responses. In this context, a correct methodological analysis and a detailed molecular investigation of the mechanisms regulating cytokine production by neutrophils in vitro is a critical and fundamental step to better understand how the release of cytokines by PMN may influence pathophysiological processes in vivo. We now describe and discuss the approach that we typically used throughout most of the last decade to characterize cytokine production by human neutrophils, as illustrated herein for a protein that is expressed and released by PMN, namely, vascular endothelial growth factor (VEGF).