Bronchoalveolar lavage cells from sarcoidosis patients and healthy controls can efficiently present antigens

The interaction between antigen-presenting cells (APC) and T lymphocytes, that recognize the antigen-HLA complex using its T cell-receptor for antigen, is of crucial importance for a subsequent specific immune response. In patients with pulmonary sarcoidosis, the local antigen-presenting capacity in the lungs has been suggested to be abnormally enhanced, and implicated in the immunopathogenesis of the disease. This study was aimed at increasing the understanding of the capacity to present antigens by APC in the lung compartment.

We used bronchoalveolar lavage (BAL) cells and paired peripheral blood mononuclear cells (PBMC) of six sarcoidosis patients and two healthy controls to stimulate in total eight well characterized T-cell clones with known HLA and antigen specificities. All subjects were HLA typed.

BAL cells of sarcoidosis patients as well as of healthy controls efficiently induced proliferation of the relevant T-cell clone in an HLA-restricted manner when adding either intact antigen or antigenic peptides.

BAL cells have the capacity to process and present antigens adequately, irrespective of whether they are derived from healthy individuals or from patients with sarcoidosis, implying the alveolar space as an important location for active immune reactions.