Anti-elastin immunity in COPD patients

Introduction: The contribution of anti-elastin immunity in COPD is subject of intense debate. Conflicting data are reported on the presence of serum auto-antibodies against elastin fragments correlating with COPD severity. As auto-immunity is driven by antigen-specific T cells, we investigated the presence of B cell and T cell responses against elastin fragments in a large sample of COPD patients and controls. Material and methods: Anti-elastin antibodies were analyzed with indirect ELISA on plasma samples of 352 COPD patients (GOLD 1-4) and 168 age-matched smoking controls. In a random subgroup of 25 patients, T-cell responses against elastin fragments were further determined with ELISPOT (IFN-g and IL-2) on peripheral blood mononuclear cells (PBMC) and compared with responses of 5 non-smoking age-matched controls. Results: Increased titers of anti-elastin antibodies were found in 14.2% (24/168) of smoking controls compared to 12.5% (44/352) of the COPD population (p=0.07). No significant correlation was found between anti-elastin antibodies and FEV1% predicted (p=0.699), nor with the presence of emphysema on CT scan (p=0.150). Despite significant responses to control antigen, ELISPOT analysis could not detect increased T cell responses against elastin in any of the individuals. Conclusion: Anti-elastin antibodies are not specific for COPD patients and do not correlate with disease severity. The absence of elastin-specific T cell responses further weakens the role of anti-elastin auto-immunity in the pathogenesis of COPD. Supported by FWO-Vlaanderen G.0687.09.