Strain-specific immune response to Haemophilus influenzae in chronic obstructive pulmonary disease

Am J Respir Crit Care Med. 2004 Feb 15;169(4):448-53. doi: 10.1164/rccm.200308-1181OC. Epub 2003 Nov 3.


Previous studies of immune response to Haemophilus influenzae after exacerbations of chronic obstructive pulmonary disease (COPD) have yielded contradictory results. Using homologous (infecting) strains and immunoassays to surface-exposed epitopes, we tested the hypothesis that adults with COPD make new antibodies to strain-specific, surface-exposed epitopes on H. influenzae after exacerbations. We collected clinical information, sputum, and serum monthly and during exacerbations from 81 patients with COPD over 56 months. Serum antibodies to H. influenzae after exacerbations associated with H. influenzae in sputum were detected with whole bacterial cell ELISA and bactericidal assays. An immune response to homologous H. influenzae occurred after 22 of 36 (61.1%) exacerbations with newly acquired strains compared with 7 of 33 (21.2%) exacerbations with preexisting strains (odds ratio [OR] = 4.4; 95%, 1.8 to 10.8; p = 0.001). An absence of an immune response was strongly associated with complement sensitivity (OR = 0.03; 95% confidence interval, 0.003 to 0.22; p = 0.001). New bactericidal antibodies developed after exacerbations were highly strain specific, showing bactericidal activity for only 11 of 90 (12.2%) heterologous strains. Development of an immune response to H. influenzae supports its role in causing exacerbations. The strain specificity of the immune response likely represents a mechanism of recurrent exacerbations.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Antibodies, Bacterial / biosynthesis*
  • Complement System Proteins / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes / immunology
  • Female
  • Haemophilus influenzae / classification
  • Haemophilus influenzae / immunology*
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / immunology*
  • Pulmonary Disease, Chronic Obstructive / microbiology
  • Serum Bactericidal Test
  • Sputum / microbiology


  • Antibodies, Bacterial
  • Epitopes
  • Complement System Proteins