Neutrophil gelatinase associated lipocalin belongs to a family of small proteins, lipocalins, engaged in the transmembrane transportation of lipophylic substances. Originally isolated from specific granules of neutrophils, it was later located in bone marrow cells as well as lung, bronchial and colon epithelial cells. The expression of neutrophil lipocalin in epithelial cells and in body fluids considerably augments during the occurrence of inflammations and some cancers. A modulation of immunity response was thus suggested to be the main function of neutrophil lipocalin as well as the bacteriostatic effect originating from competition between neutrophil lipocalin and bacteria for siderophoric iron. Forming protective complexes with gelatinase B, the neutrophil lipocalin is implicated in regulatory processes of physiological and pathological rebuilding of tissues, mainly in the angiogenesis. The determination of neutrophil lipocalin levels in body fluids able to discriminate between bacterial and viral infections provides a powerful diagnostic tool. The examination of neutrophil lipocalin in the sera and urine of patients at risk of renal failure offers a very early marker of this acute state. Neutrophil lipocalin represents a sensitive non-invasive marker of renal ischemia and in patients with cystic fibrosis the marker of acute pulmonary exacerbation. Discussions have been conducted regarding the role of neutrophil lipocalin as an early marker of pancreatic cancer or of neutrophilic activation in severe cases of bowel diseases.

        Key words: Lcn2, NGAL, neutrophil, siderophores, angiogenesis, bacterial infection, ischemia, cystic fibrosis, acute renal failure, acute pulmonary exacerbation.