Complement Factors C3a and C5a Are Increased in Bronchoalveolar Lavage Fluid After Segmental Allergen Provocation in Subjects With Asthma

Am J Respir Crit Care Med. 2001 Nov 15;164(10 Pt 1):1841-3. doi: 10.1164/ajrccm.164.10.2010096.


Allergic asthma is thought to be the result of an inappropriate specific immune response against common environmental antigens. However, studies of animal asthma models have also linked the innate immune system, in particular complement factors C3a and C5, to murine airway hyperresponsiveness. Because the possible role of these anaphylatoxins in patients with asthma is not understood, we tested the hypothesis that C3a and C5a will increase in the bronchoalveolar lavage (BAL) fluid of patients with asthma after segmental allergen provocation. In a group of 15 subjects with mild asthma we found a significant upregulation of C3a and C5a 24 h after allergen challenge compared with baseline values (p < 0.01). In a control group of healthy volunteers the concentrations remained basically unchanged. Furthermore, we found a strong correlation between both anaphylatoxins and the number of eosinophils (p < 0.01) and, to a lesser degree, with the number of neutrophils (p < 0.05) in BAL fluid. These data suggest a contribution of anaphylatoxins C3a and C5a to the pathogenesis in asthma. However, the pathogenic role of these substances in relation to asthma remains to be elucidated, for example, by using anaphylatoxin receptor blockers as a possible new therapeutic principle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Asthma / classification
  • Asthma / complications
  • Asthma / diagnosis
  • Asthma / immunology*
  • Bronchial Hyperreactivity / etiology
  • Bronchial Provocation Tests / adverse effects*
  • Bronchial Provocation Tests / methods
  • Bronchoalveolar Lavage Fluid / chemistry*
  • Bronchoalveolar Lavage Fluid / immunology*
  • Bronchoconstrictor Agents / adverse effects*
  • Case-Control Studies
  • Complement C3a / analysis*
  • Complement C3a / immunology*
  • Complement C5a / analysis*
  • Complement C5a / immunology*
  • Eosinophils / immunology
  • Female
  • Forced Expiratory Volume / drug effects
  • Histamine / adverse effects*
  • Humans
  • Inflammation
  • Leukocyte Count
  • Male
  • Neutrophils / immunology
  • Severity of Illness Index
  • Statistics, Nonparametric
  • Time Factors


  • Bronchoconstrictor Agents
  • Complement C3a
  • Complement C5a
  • Histamine