Autoimmune T cell responses to antigenic peptides presented by bronchoalveolar lavage cell HLA-DR molecules in sarcoidosis

The etiology of sarcoidosis remains unknown. Recently, by mass spectrometric sequencing of peptides eluted from HLA-DR molecules of bronchoalveolar lavage (BAL) cells from DRB1⁎0301pos patients, we identified potential self-antigens in sarcoidosis. The aim of the present study was to investigate the capacity of selected peptides to stimulate lung and blood T cells of sarcoidosis patients using an interferon-γ ELISPOT assay. In peripheral blood, there were strong T cell responses to a peptide derived from the cytoskeletal protein vimentin in 6 out of 11 DRB1⁎0301pos patients with active disease but not in patients with other HLA types. BAL T cell responses against peptides derived from ATP synthase or from lysyl-tRNA synthetase were detected in DRB1⁎0301pos as well as DRB1⁎0301neg patients. By using antigenic peptides presented in vivo in the lungs of sarcoidosis patients, we have identified blood and lung T cell autoimmune responses that may help sustain the inflammation in this disease.