Interleukin-2 receptor gene expression by bronchoalveolar lavage lymphocytes in pulmonary sarcoidosis.

Current concepts of the immunopathogenesis of sarcoidosis favor a central role of activated, interleukin-2 (IL-2) producing helper T-cells at sites of inflammation. Normally, activated T-cells release IL-2 and express IL-2 receptors (IL-2R). IL-2R+ cells, however, are not uniformly found in patients with clinically active disease. To determine whether the lack of IL-2R+ cells is caused by a dysregulation of the IL-2R gene or by the mode of T-cell activation in pulmonary sarcoidosis, we quantified IL-2 and IL-2R m-RNA transcripts, IL-2 release, and IL-2R surface protein in peripheral blood lymphocytes of patients with sarcoidosis and normal control subjects before and after in vitro stimulat…