Expression of priming-associated cellular markers on neutrophils during an exacerbation of COPD

Chronic inflammation of the airways is a hallmark of chronic obstructive pulmonary disease (COPD). We investigated the kinetics of priming of inflammatory cells in peripheral blood during exacerbations of COPD and during the resolution phase. Modulation of the leukocyte compartment as a consequence of systemic activation by cytokines/chemokines was determined by measuring the expression of priming-associated epitopes by novel antibodies designated A17 and A27. Furthermore, H2O2 was determined in breath condensate as a read out for local inflammation. Leukocytes were obtained from COPD patients (GOLD II-IV) during and after an exacerbation of their disease. During an exacerbation the expression of priming epitopes on leukocytes was increased. This priming phenotype disappeared upon treatment with intravenous corticosteroids. Similarly, H2O2 levels in breath condensate were also increased during an exacerbation and decreased upon treatment. We conclude that the activation status of neutrophils in the systemic compartment can be used as a read-out for systemic innate immune signals involved in the pathogenesis of COPD. The correlation between H2O2 in exhaled air with A27 priming on neutrophils showed that local inflammation has systemic effects on cells of the innate immune system.