SELECTED ARTICLES FROM THE RECENT LITERATURE 2004

10/8/04

Safety and application of induced sputum analysis in childhood asthma  

Summary
Background - With the recognition that bronchial inflammation (BI) plays a major pathogenic role in asthma, many studies of BI have been carried out to assess the natural history of asthma and treatment effects. More recently, induced sputum (IS) specimens obtained in adults after inhalation of hypertonic saline solutions have been found to provide information about BI similar to that seen in endoscopic bronchial biopsies with much less potential for adverse effects when avoiding the more invasive biopsy approach. But can the IS approach be carried out safely and productively in children?

Findings - Covar et al of the National Jewish Medical and Research Center in Denver, CO attempted the use of IS to assess BI in children with persistent asthma enrolled in their site as part of the multi-institutional Children's Asthma Management Program (CAMP). They found that the IS procedure was relatively safe and well tolerated by children. However, in 23% of the children an IS specimen could not be induced. Also, the SI procedure induced bronchoconstriction in 8% of the children despite pre-treatment with an inhaled beta agonist.

In the adequate specimen obtained, the investigators found a higher % eosinophils in sputum of atopics. Those with lower FEV-1/fvc ratios, greater post-bronchodilator reversibility, greater asthma severity (with more need for oral steroid treatment courses) had higher levels of sputum and serum eosinophil cationic protein, and exhaled nitric oxide (NO) levels.

In those children treated with inhaled budesonide there was a higher pre-bronchodilator FEV-1, as well as a lower % eosinophils in the IS and lower exhaled NO levels when compared to those receiving placebo treatment. However, the IS findings in nedocromil and placebo treated asthmatics were not different.

Reference
J Allergy Clin Immunol 2004;114:575-82

Editor's Comments
This report points out the value of IS findings in the investigation of BI in childhood asthma and its treatment. However, the fact that IS was not technically successful in almost one of four asthmatic children studied, along with broncho-spasm induced by the IS procedure in 8% of the children, suggest that this approach is still a predominantly research tool and not yet appropriate for community practice management of childhood asthma.

 

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