What Is New In Small Airways Research
By Ves Dimov, MD
Allergist/Immunologist, Assistant Professor, University of Chicago
Biomarker surrogates (FENO, blood eosinophils) do not predict sputum eosinophil percentages in asthmatic patients
Sputum eosinophils are a strong predictor of airway inflammation and exacerbations. Sputum neutrophils indicate a different severe asthma phenotype that is potentially less responsive to Th2-targeted therapy such as inhaled corticosteroids.
This Wake Forest Severe Asthma Research Program based in the United States included 328 patients with asthma. Blood eosinophil counts, FENO levels, and total IgE levels did not accurately predict sputum eosinophil percentages. Age, FEV1 percent predicted, and blood neutrophil counts were similarly unsatisfactory for the prediction of sputum neutrophil percentages.
FENO levels, IgE levels, blood eosinophil and neutrophil counts, FEV1, and age are poor surrogates for predicting sputum eosinophil and neutrophil percentages.
Source: Hastle A, Moore W, Li H, Rector B, Ortega V et al. Biomarker surrogates do not accurately predict sputum eosinophil and neutrophil percentages in asthmatic subjects. The Journal of Allergy and Clinical Immunology, 2013; 132(1): 72-80. (doi:10.1016/j.jaci.2013.03.044)
Mycoplasma pneumoniae is associated with worsening asthma. Children with asthma may have poor humoral immune responses to it.
The presence of Mycoplasma pneumoniae (M pneumoniae) has been associated with worsening asthma in children. This study from Texas, USA, enrolled 143 children (53 with acute asthma, 26 with refractory asthma, and 64 healthy controls; aged 5-17 years) during a 20-month period.
M pneumoniae was detected in 64% of patients with acute asthma, 65% with refractory asthma, and 56% of healthy controls. Children with asthma had lower antibody levels to M pneumoniae compared with healthy controls. Asthma control and quality of life scores were lower in M pneumoniae–positive patients with asthma.
M pneumoniae detection is associated with worsening asthma, and children with asthma may have poor humoral immune responses to M pneumoniae.
Editor’s note: The natural follow-up question from this study is to ask if treatment of M pneumoniae would improve outcomes in this patient population. Previous studies of macrolides in patients with uncontrolled asthma have been mostly inconclusive.
Source: Wood PR, Hill VL, Burks ML, Peters JI, Singh H et al. Mycoplasma pneumoniae in children with acute and refractory asthma. Annals of Allergy, Asthma & Immunology, 2013; 110(5): 328-334e1.
Patients are more adherent to ICS+LABA therapy than ICS+LTRA therapy (ICS+LABA works better too, regardless of adherence)
A recent study sponsored by the British NHS suggested that the use of leukotriene receptor antagonists (LTRAs) in addition to inhaled corticosteroids (ICSs) in asthmatic patients provides comparable benefits to the addition of long-acting β-agonists (LABAs) to ICSs.
This study from Canada included 1,032 adults with asthma receiving ICS+LTRA therapy versus ICS+LABA therapy after a period of monotherapy with an ICS (mean age 27 years; 52.5% female).
Adherence was higher in the ICS+LABA group compared with the ICS+LTRA group. ICS+LTRA therapy was associated with more asthma-related outpatient visits, medication dispensations, and dispensation of reliever medications. Dispensation of oral corticosteroids and rate of asthma exacerbations were also higher in the ICS+LTRA group.
In a real-world clinical setting subjects were more adherent to ICS+LABA therapy than ICS+LTRA therapy. ICS+LABA therapy seems to be more effective than ICS+LTRA therapy in the management of asthma, regardless of adherence
Source: Sadatsafavi M, Lynd L, Marra C, Bedouch P, FitzGerald M. Comparative outcomes of leukotriene receptor antagonists and long-acting β-agonists as add-on therapy in asthmatic patients: A population-based study. The Journal of Allergy and Clinical Immunology, 2013; 132(1): 63-69.