Measurement of pro-inflammatory and anti-inflammatory cytokines in exhaled breath condensates

Abstract

Rationale Asthma is a chronic, inflammatory respiratory disease. Exhaled markers of inflammation measured noninvasively may reveal information on the changes seen with different stages of asthma as pro-inflammatory and anti-inflammatory components are hypothesized to contribute to the pathological changes manifested in all stages of asthma. Methods Recruited individuals included 17 subjects with asthma and 11 control subjects. Each person was given standardized pulmonary function tests and exhaled breath condensates (EBC) were collected. Inflammatory and anti-inflammatory markers including TNF, IL-1, IL-4, IL-10 and IFN were collected and measured with a highly sensitive chemiluminescent enzyme immunoassay (ELISA) using a Bio-Tek Precision 2000 Automated Pipetting System. Luminometer was used to read the plates. The cytokines were measured at picograms/ml. Regression analysis was performed on the background corrected RLUs (relative light units) from the standard curve and unknown sample concentrations are interpolated. Reproducible results were seen. Results The analysis of markers of EBC reveals no definite trends in the pro-inflammatory cytokines including TNF, IL-1, IL-4 and the anti-inflmmatory cytokine IL-10 and IFN in asthmatic subjects. Many problems were identified which may influence the results including medications. The detection of picograms/ml of cytokines and studying their ratios will enhance our understanding of their additive, synergistic and antagonistic effects. Conclusions We have demonstrated the ability to reproducibly measure inflammatory and anti-inflammatory cytokines in EBC. This should allow us to further clarify their role in the development of asthma.