title: The influence of persistent pathogens on circulating levels of inflammatory markers: a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis.
abstract: BACKGROUND
  Systemic inflammation is linked to cardiovascular risk, but the influence of persistent pathogens, which are conventionally dichotomously categorized, on circulating levels of inflammatory markers is not clear. Antibody levels of pathogens have not been examined in relation to inflammation.
  
  
  METHODS
  Using data from a subsample of the Multi-Ethnic Study of Atherosclerosis, we examined circulating levels of interleukin-6 (IL-6), C-reactive protein (CRP) and fibrinogen in relation to five common persistent pathogens: cytomegalovirus, herpes simplex virus-1, Hepatitis A virus, Helicobacter pylori and Chlamydia pneumoniae. We tested the hypothesis that the number of seropositive pathogens (based on conventional cut-off points) would not be as sensitive a marker of inflammation as immune response measured by antibody levels to pathogens.
  
  
  RESULTS
  High antibody response to multiple pathogens showed graded and significant associations with IL-6 (p < 0.001), CRP (p = 0.04) and fibrinogen (p = 0.001), whereas seropositive pathogen burden did not. In multiple linear regression models, high antibody response to multiple pathogens maintained a positive association only with IL-6 (4.4% per pathogen exhibiting high antibody response, 95% CI 0.0-8.9).
  
  
  CONCLUSIONS
  High antibody response to pathogens was a more consistent marker of inflammatory outcomes compared to seropositivity alone and high antibody response to multiple pathogens was a stronger marker compared to any single pathogen.
authors.affiliation: Department of Epidemiology, University of Michigan School of Public Health, 1415 Washington Heights, Room 3659, Ann Arbor, MI 48109, USA.
authors.forename: Aydin
authors.initials: A
authors.lastname: Nazmi
authors.forename: Ana V
authors.initials: AV
authors.lastname: Diez-Roux
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Jenny
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Tsai
authors.forename: Moyses
authors.initials: M
authors.lastname: Szklo
authors.forename: Allison E
authors.initials: AE
authors.lastname: Aiello
mesh_terms: D000368:Aged; D000906:Antibodies / Q000032:analysis; D050197:Atherosclerosis / Q000208:ethnology / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002689:Chlamydia / Q000276:immunology*; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007107:Immune System / Q000473:pathology; D007249:Inflammation; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014780:Viruses / Q000276:immunology*
chemical_list: D000906:Antibodies; D015415:Biomarkers; D015850:Interleukin-6; D005340:Fibrinogen; D002097:C-Reactive Protein