THE LYMPHOCYTIC ALVEOLITIS IN SARCOIDOSIS IS ASSOCIATED WITH INCREASED AMOUNTS OF SOLUBLE AND CELL-BOUND ADHESION MOLECULES IN BRONCHOALVEOLAR LAVAGE FLUID AND SERUM

Objectives. Pulmonary sarcoidosis is a chronic inflammatory disorder o f unknown aetiology accompanied by a lymphocytic alveolitis. It is lik ely that a selective and temporal expression of adhesion molecules pla ys a crucial role in the recruitment of cells to the inflammatory site . We investigated the expression of adhesion molecules on alveolar T-l ymphocytes and in bronchoalveolar lavage (BAL) fluid and serum to eluc idate mechanisms behind the accumulation of cells in the lung in sarco idosis. Design. In a cross-sectional study in patients with active and inactive sarcoidosis and in healthy volunteers, we examined, in serum and in BAL fluid, the soluble adhesion molecules, VCAM-1, ICAM-1, and P-, E- and L-selectin. In addition, the expressions of alpha(4)-beta( 1) (VLA-4) and alpha(5)-beta(1) (VLA-5) integrins on alveolar T-lympho cytes were analysed. Setting. The subjects attended the outpatient cli nic at the Division of Respiratory Medicine, Karolinska Hospital,Stock holm, Sweden. Subjects. Nineteen sarcoidosis patients, nine with clini cally active disease, and 13 healthy volunteers were included in the s tudy. The sarcoidosis diagnosis was based on a typical histological an d/or clinical (symptoms, radiograph, lung function) picture. Results. In sarcoidosis patients, particularly in those with active disease, an increase of the expressions of beta(1)-integrins was accompanied by e levated concentrations in BAL fluid of soluble VCAM-1. In serum, the l evels of E-selectin and ICAM-1 were significantly higher in patients w ith active disease than in those with inactive disease and controls. C onclusions. The findings offer some mechanistic explanations as to how the cell-rich alveolitis in sarcoidosis occurs, and furthermore sugge st additional markers, such as s-ICAM-1, for assessment of disease act ivity.