RESUMEN
Normal polymorphonuclear neutrophils (PMN) in the circulation are resting cells expressing small numbers of low affinity receptors. During inflammation they are upregulated to increase expression of high affinity receptors and discharge both primary and secondary granules. This is reflected by a pattern of changes which can be detected in PMN from the circulation of patients with infection, trauma or burns. Different patterns of abnormality occur in patients with systemic disease and increased risk of infection such as diabetes and renal failure. Functional defects also occur in PMN from patients with acquired blood disorders. It is likely that PMN contribute to tissue damage in inflammatory and vascular diseases so that drugs which modulate PMN function will be of future therapeutic benefit.