Serum eosinophilic cationic protein and lactoferrin related to smoking history and lung function.

Some smokers have an accelerated loss of lung function, possibly due to a chronic bronchial inflammation in which granulocytes are involved. Eosinophil cationic protein (ECP) and lactoferrin (LF) are granule proteins in the eosinophil and neutrophil granulocyte, respectively. We wanted to investigate the relationship of serum (s) ECP and LF concentrations to smoking history and lung function alteration. This partly cross-sectional and partly prospective study included 98 nonatopic smokers and 31 lifetime nonsmokers. As participants in a smoking cessation programme, 50 of the 98 smokers ceased smoking for > or = 1 year. Smoking history, lung function and blood samples were obtained at the start of the study, and smokers and ex-smokers also gave blood samples 3, 6 and 12 months later. s-ECP and s-LF were elevated in smokers compared to people who had never smoked. s-ECP was linearly associated with daily cigarette consumption and forced expiratory volume in one second (FEV1) residuals. In a multiple linear regression analysis, low s-ECP and high s-LF were associated with decreased FEV1 residuals. s-ECP and s-LF together accounted for 10.2% of the variation in FEV1 residuals. After smoking cessation, s-ECP and s-LF decreased within 6 months. s-ECP and s-LF are raised in smokers, and may serve as indicators of granulocyte activation. We speculate that they might contribute to prediction of accelerated lung function loss in smokers, but this question needs further investigation in a prospective study.