0
Original Research: ASTHMA |

Sputum Eosinophils and the Response of Exercise-Induced Bronchoconstriction to Corticosteroid in Asthma*

MyLinh Duong, MBBS; Padmaja Subbarao, MD, MSc; Ellinor Adelroth, MD, PhD; George Obminski, BSc; Tara Strinich, BSc; Mark Inman, MD, PhD; Soren Pedersen, MD, PhD; Paul M. O’Byrne, MB, FCCP
Author and Funding Information

*From the Department of Medicine (Drs. Duong, Inman, and O’Byrne, Mr. Obminski, and Ms. Strinich), McMaster University, Hamilton, ON, Canada; Hospital for Sick Children (Dr. Subbarao), University of Toronto, Toronto, ON, Canada; Umea University (Dr. Adelroth), Umea, Sweden; and the University of Southern Denmark (Dr. Pedersen), Kolding, Denmark.

Correspondence to: MyLinh Duong, MBBS, McMaster University, 1200 Main St West, Room 3U-24, Hamilton, ON, Canada L8N 3Z5; e-mail: duongmy@mcmaster.ca



Chest. 2008;133(2):404-411. doi:10.1378/chest.07-2048
Text Size: A A A
Published online

Background: The relationship between eosinophilic airway inflammation and exercise-induced bronchoconstriction (EIB), and the response to inhaled corticosteroid (ICS) therapy was examined.

Methods: Twenty-six steroid-naïve asthmatic patients with EIB were randomized to two parallel, double-blind, crossover study arms (13 subjects in each arm). Each arm compared two dose levels of inhaled ciclesonide that were administered for 3 weeks with a washout period of 3 to 8 weeks, as follows: (1) 40 vs 160 μg daily; and (2) 80 vs 320 μg daily. Baseline and weekly assessments with exercise challenge and sputum analysis were performed.

Results: Data were pooled and demonstrated that 10 subjects had baseline sputum eosinophilia ≥ 5%. Only high-dose ICS therapy (ie, 160 and 320 μg) significantly attenuated the sputum eosinophil percentage. Sputum eosinophil percentage significantly correlated with EIB severity, and predicted the magnitude and temporal response of EIB to high-dose therapy, but not to low-dose therapy (ie, 40 and 80 μg). Low-dose ICS therapy provided a significant reduction in EIB at 1 week, with little additional improvement thereafter, irrespective of baseline sputum eosinophil counts. In contrast, high-dose ICS therapy provided a significantly greater improvement in EIB in subjects with sputum eosinophilia compared to those with an eosinophil count of < 5%. The difference between the eosinophilic groups in the magnitude of improvement in EIB was evident after the first week of high-dose ICS therapy and increased with time.

Conclusions: These results suggest that eosinophilic airway inflammation may be important in modifying the severity of EIB and the response to ICS therapy. Measurements of sputum eosinophil percentage may, therefore, be useful in predicting the magnitude and temporal response of EIB to different dose levels of ICSs.

Trial registration: clinicaltrial.gov; Identifier: NCT00525772

Figures in this Article

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Figures

Tables

References

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Find Similar Articles
CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543