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document
Pathological features and inhaled corticosteroid response of eosinophilic and non-eosinophilic asthma . BACKGROUND Non-eosinophilic asthma is a potentially important clinicopathological phenotype since there is evidence that it responds poorly to inhaled corticosteroid therapy . However , little is known about the underlying airway immunopathology and there are no data from placebo-controlled studies examining the effect of inhaled corticosteroids . METHODS Airway immunopathology was investigated using induced sputum , bronchial biopsies , bronchial wash and bronchoalveolar lavage in 12 patients with symptomatic eosinophilic asthma , 11 patients with non-eosinophilic asthma and 10 healthy controls . The patients with non-eosinophilic asthma and 6 different patients with eosinophilic asthma entered a randomised , double-blind , placebo-controlled crossover study in which the effects of inhaled mometasone 400 microg once daily for 8 weeks on airway responsiveness and asthma quality of life were investigated . RESULTS Patients with non-eosinophilic asthma had absence of eosinophils in the mucosa ( median 4.4 cells/mm ( 2 ) vs 23 cells/mm ( 2 ) in eosinophilic asthma and 0 cells/mm ( 2 ) in normal controls ; p = 0.03 ) and normal subepithelial layer thickness ( 5.8 microm vs 10.3 microm in eosinophilic asthma and 5.1 microm in controls , p = 0.002 ) . Non-eosinophilic and eosinophilic asthma groups had increased mast cell numbers in the airway smooth muscle compared with normal controls ( 9 vs 8 vs 0 cells/mm ( 2 ) , p = 0.016 ) . Compared with placebo , 8 weeks of treatment with inhaled mometasone led to less improvement in methacholine PC ( 20 ) ( 0.5 vs 5.5 doubling concentrations , 95 % CI of difference 1.1 to 9.1 ; p = 0.018 ) and asthma quality of life ( 0.2 vs 1.0 points , 95 % CI of difference 0.27 to 1.43 ; p = 0.008 ) . CONCLUSIONS Non-eosinophilic asthma represents a pathologically distinct disease phenotype which is characterised by the absence of airway eosinophilia , normal subepithelial layer thickness and a poor short-term response to treatment with inhaled corticosteroids .
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Intervention_Control
placebo-controlled
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Intervention_Pharmacological
inhaled mometasone 400 microg
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Outcome_Physical
airway responsiveness
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Outcome_Physical
asthma quality of life
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Outcome_Physical
absence of eosinophils in the mucosa
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Outcome_Physical
subepithelial layer thickness
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Outcome_Physical
mast cell numbers
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Outcome_Other
improvement
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Outcome_Physical
methacholine PC ( 20 )
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Outcome_Physical
asthma quality of life
30102
Outcome_Physical
airway eosinophilia
30103
Outcome_Physical
subepithelial layer thickness
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Outcome_Physical
short-term response to treatment
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Participant_Condition
eosinophilic and non-eosinophilic asthma
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Participant_Sample-size
12 patients
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Participant_Condition
symptomatic eosinophilic asthma
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Participant_Sample-size
11 patients
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Participant_Condition
non-eosinophilic asthma
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Participant_Sample-size
10
30111
Participant_Condition
healthy controls
30112
Participant_Sample-size
6 different patients