Poster Presentation Australasian Society for Immunology Annual Scientific Meeting 2014

Chlamydia pneumoniae infection of dendritic cells induces differential responses in acute and stable asthmatic patients (#161)

Danica Hickey 1 , Mohammed Imran Hossain 1 , Ian Yang , Andrew Burke , Pat Aldons , Mark Dawson , Ken Beagley 1
  1. Queensland University of Technology, Kelvin Grove, QLD, Australia
Introduction: Asthma is a common chronic inflammatory condition of the airways characterized by recurrent episodes of airway obstruction and wheezing. Respiratory infections are hypothesized to alter immune regulation which contributes significantly to asthma. Sero‐epidemiological studies has shown that many asthmatics have elevated antibody levels to C. pneumoniae, suggestive of persistent infection. Dendritic cells (DCs) are important in bridging the innate and the adaptive immunity in response to pathogens. This study investigated differences in production of immune parameters by C. pnuemoniae-infected DCs isolated from stable and acute asthmatic patients.

Methods. Clinically defined asthma patients were recruited from Prince Charles Hospital Brisbane and defined as; stable asthmatics which did not require oral steroids; or acute asmatics that had presented to emergency with severe exacerbation requiring systemic steroids.  PBMCs were isolated from whole blood (prior to Ssteroid treatment) and DCs derived in vitro from isolate CD14 monocytes. Using microarray and flow analysis, changes in immune regulation genes, maturation marker activation and  cytokines production during C. Pneumoniae pneumoniae infection was compared between each asthma cohort .

Results: Although DCs activation markers CD86CD80, CD83, CD80 CD86 and HLA-DR did not differ between each asthma group, microarray analysis showed a significant up regulation of 73 genes and down regulation of 17 genes during C. pnuemoniae infection of DCs isolated from stable compared to acute asthmatic patients. Specifically, in stable patients we observed a  significant up-regulation IL-20, IL-36γ, IL-17 and matrix metallpepitidases, including MMP1 and MMP19 mRNA. Additionally, we observed a significant increase in the amount (pg/ml) of produced IL-4, IL-10 and TNFα in the stable asthmatics.

Conclusion: C. Pnuemoniae-infected DCs from stable asthmatics show a significantly increased expression/secretion of cytokines and matrix remodelling genes (MMPs) compared to the cute asthmatic group. This suggests that DC activation leading to the production of immune modulators i.e. cytokines may help modulate or reduce a severe asthmatic exacerbation event.