Allergen-induced increase in non-allergic bronchial reactivity

Authors

  • D. W. COCKCROFT,

    1. Regional Chest and Allergy Unit, Department of Medicine, St Joseph's Hospital, and McMaster University, Hamilton, Ontario, Canada
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  • R. E. RUFFIN,

    1. Regional Chest and Allergy Unit, Department of Medicine, St Joseph's Hospital, and McMaster University, Hamilton, Ontario, Canada
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  • J. DOLOVICH,

    1. Regional Chest and Allergy Unit, Department of Medicine, St Joseph's Hospital, and McMaster University, Hamilton, Ontario, Canada
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  • F. E. HARGREAVE

    Corresponding author
    1. Regional Chest and Allergy Unit, Department of Medicine, St Joseph's Hospital, and McMaster University, Hamilton, Ontario, Canada
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Dr F. E. Hargreave, Regional Chest and Allergy Unit, St Joseph's Hospital, 50 Charlton Avenue East, Hamilton, Ontario, Canada L8N 1Y4.

Summary

Non-allergic bronchial hyper-reactivity is a feature of most patients with asthma. We have measured non-allergic bronchial reactivity to inhaled histamine and methacholine in thirteen asthmatic subjects before and after allergen inhalation in the laboratory. The allergen inhalation produced mild early asthmatic responses (19–40% FEV1 fall) in all thirteen, additional definite late asthmatic responses (17–29% FEV1 fall) in four, and equivocal late asthmatic responses (5–11% FEV1 fall) in five. Following allergen inhalation, non-allergic bronchial reactivity increased in seven for up to 7 days. The seven included all four with definite late asthmatic responses and three of the five with equivocal late asthmatic responses. We conclude that allergens make asthma worse, partly through non-allergic mechanisms, and that avoidance of allergens is important in reducing non-allergic bronchial hyper-reactivity.

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