Thanks to the application of this new immunoproteomic strategy, the authors could isolate from sputum of CF subjects with acute exacerbations a variety of chronic inflammation-associated autoantigens (e.g., enolase 1B, myeloperoxidase, the regulatory subunit calgranulin B of the CF antigen complex and antigenic fragments of IgG heavy chains). Here, S100A9 is linked to cystic fibrosis.