A critical look at blood samples in CB and COAD.

Few studies have utilized measurements of blood variables to estimate the clinical activity of chronic bronchitis in relation to clinical trials. In one study, we have followed such patients with repeated measurements of serum levels of lactoferrin, myeloperoxidase and lysozyme as markers of neutrophil and monocyte/macrophage activity. We showed that these patients have raised lysozyme levels, as signs of ongoing activation of the macrophage population, irrespective of the presence of infectious exacerbations. Lactoferrin and myeloperoxidase levels, on the other hand, showed large variations with peaks mostly coinciding with the infectious exacerbations. In another study, we made repeated measurements during a 6-months' period of a number of neutrophil activities. These data showed increased activities with respect to migration and oxidative metabolism during the period of increased numbers of infectious exacerbations. All but one variable became normal during periods of few infectious. Thus, the lucigenin-enhanced chemiluminescence was subnormal during this period suggesting an abnormality of neutrophil oxidative metabolism in patients with chronic bronchitis. We conclude that the monitoring of markers of inflammatory cell activity in serum may be useful as indicators of the clinical activity of chronic bronchitis and that the measurement of functional activities of the neutrophil is dependent on seasonal variations in the exposure to infectious agents in the community.