|Article Type:||Brief article|
Asthma (Patient outcomes)
Respiratory agents (Dosage and administration)
Respiratory agents (Patient outcomes)
|Publication:||Name: Townsend Letter Publisher: The Townsend Letter Group Audience: General; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2012 The Townsend Letter Group ISSN: 1940-5464|
|Issue:||Date: April, 2012 Source Issue: 345|
|Product:||Product Code: 2834400 Respiratory Preparations; 2834440 Ethical Cough & Cold Combinations NAICS Code: 325412 Pharmaceutical Preparation Manufacturing SIC Code: 2833 Medicinals and botanicals; 2834 Pharmaceutical preparations|
|Geographic:||Geographic Scope: United States Geographic Code: 1USA United States|
Corticosteroid medications for asthma target eosinophils, a type of
white blood cell that produces inflammation in the respiratory tract.
Unfortunately, a large percentage of asthma sufferers do not have
eosinophil-caused inflammation, according to a January 2012 study.
Corticosteroids (prednisone, Aerobid, Azmacort, Flovent, and Symbiocort)
cannot help them.
In their 2012 study, Kelly Wong McGrath and colleagues analyzed lung mucus samples from 995 asthmatic patients enrolled in the Asthma Clinical Research Network clinical trials. Only 53% of these patients had eosinophils in their mucus samples; 47% did not. While two weeks of antiinflammatory therapy improved airflow in those with eosinophilic asthma, the medications did not help those with non-eosinophilic asthma. The bronchodilator albuterol produced similar results in both types of asthma.
If eosinophilia isn't the cause of 47% of asthma cases, what is? One possibility lies in a 2011 Dutch investigation of delayed asthmatic response (DYAR). DYAR occurs between 16 and 32 hours after bronchial exposure to an allergen, reaches a climax between 32 and 48 hours, and then resolves - within 56 hours after the exposure. In this study, Dutch researchers measured 15 substances in the blood 1 leukotriene B(4) (LTB), LTC(4), LTC(4), LTE(4), prostaglandin D(2) (PGD ), PGE(2), PGF(2) (a), thromboxane B(2), lipoxin A(4), eosinophil cationic protein, eosinophil-derived neurotoxin/eosinophil protein X, eosinophilic peroxidase, myeloperoxidase, histamine and tryptase - and five substances in urine before and up to 72 hours after a bronchial allergen challenge. The only measurements that increased after the challenge were blood concentrations of leukotriene B(4) (<0.05) and myeloperoxidase (p<0.05) at 24, 36, and 48 hours. No other substance levels changed significantly. "These results would indicate an active and prominent involvement of neutrophils, in addition to the previously demonstrated role of the Thl lymphocytes, in the clinical DYAR" says Z. Pelikan.
Goodman B. Why don't some people with asthma respond to medication? WebMD Health News. January 6, 2012. Available at www.vvebmd.com. Accessed January 9, 2012.
McGrath KW, Icitovic N, Boushey HA, et al. A large subgroup of mild-to-moderate asthma is persistently non-eosinophilic [abstract]. Am I Respir Crit Care Med. January 20, 2012. doi:10.1164/rccm.201109-16400C. Available at http://ajrccm.atsjournals.org/content/early/2012/01/18/rccm.201109-1640OC.abstract. Accessed January 25, 2012.
Pelikan Z. Delayed asthmatic response to bronchial challenge with allergen-mediators, eicosanoids, eosinophil and neutrophil constituents in the blood and urine (abstract). Respiration. 2011;82(3):225-236. Available at www.ncbi.nlm.nih.gov/pubmed/21454958. Accessed January 25, 2012.
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