SELECTED ARTICLES FROM THE RECENT LITERATURE 2006

11/17/06

Eosinophil cationic protein - useful in asthma?

Summary
Background - In most cases of persistent asthma (PA), there is an eosinophil (Eos) -rich inflammatory reaction in the airways. When Eos become activated in asthma, they release cationic components such as eosinophilic cationic protein (ECP). Several groups have concluded that measurements of ECP levels is helpful in understanding the pathogenesis of PA and monitoring its course.

Findings - Kah et al of the Natl Univ of Singapore carried out a systematic review of the studies of serum ECP levels in PA. They concluded that serum ECP levels correlate significantly with the degree of airway inflammation but not with degrees of bronchial reactivity to agents such as inhaled methacholine. Increased serum ECP levels are not diagnostic for asthma, being found in patients with marked atopy but without asthma. However, such ECP levels in known asthmatics are useful in assessing the severity of PA, its control (and compliance with) inhaled corticosteroids (ICS) therapy and any decreasing control as the ICS dosage is reduced. There are other possible factors affecting serum ECP levels of which smoking is the only one detected to date that is of clinical significance.

Reference
Respir Med 2006;Oct 9, E pub

Editor's Comments
The use of serum ECP levels to follow the course (and treatment) of PA appears to be more popular in Europe than in the USA. Perhaps there are subsets of PA patients in which this assay will be particularly helpful.

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