NEW YORK (Reuters Health) May 02, 2002 - Human neutrophil lipocalin (HNL) appears to be a marker for local neutrophil activation in patients with ulcerative colitis (UC), according to a recent report by Swedish researchers.
Neutrophils are thought to mediate much of the damage associated with UC. However, it has been difficult to identify a marker that is specific for neutrophil activation, since many of the proteins released by activated neutrophils are also secreted by other cell types.
Recently, Dr. Marie Carlson, from the University of Uppsala, and colleagues purified and characterized HNL, a protein that appears to be unique to neutrophils. In the current study, the researchers measured levels of the protein in colon perfusion fluids and biopsy samples obtained from 18 UC patients and 18 healthy control subjects.
Fluid levels of HNL and myeloperoxidase, a protein released by several cell types, were 10 to 55 times higher in UC patients than in control subjects. Furthermore, in biopsy specimens from patients with active colonic inflammation only neutrophils stained positive with anti-HNL antibodies.
HNL levels correlated with levels of granulocyte/macrophage-colony stimulating factor and interleukin-8, suggesting that these cytokines may play a role in neutrophil activation, the authors note in the April issue of Gut.
"The increased release of HNL and myeloperoxidase in colorectal perfusion fluids indicates neutrophil involvement in the local inflammatory process, and suggests that HNL may serve as a specific marker of intestinal neutrophil activation in UC," the researchers conclude.