Reduced pulmonary function is associated with enhanced inflammation and tissue inhibitor of metalloproteinase 1 concentration in the bronchoalveolar lavage fluid of patients with lung parenchymal sarcoidosis.

Lung parenchymal disease is associated with reduced pulmonary function in patients with sarcoidosis, however, the underlying pathophysiology of the condition is unclear. The present study was conducted to characterize the association between pulmonary function and bronchoalveolar lavage (BAL) findings in patients with sarcoidosis. Twenty-three patients with lung parenchymal disease (stage 2) and twenty-five patients without lung parenchymal disease (stage 1) underwent pulmonary function tests, including blood gas analysis, spirometry and diffusing capacity for carbon monoxide (DLco) and BAL, to determine the number of inflammatory cells, matrix metalloproteinase (MMP) 9 activity and tissue inhibitor of metalloproteinase (TIMP) 1 concentration in the lower airway. Vital capacity (VC) to its reference value (%VC) and %DLco were significantly reduced in patients with stage 2 disease in comparison with those with stage 1 disease. BAL fluid analysis revealed that the numbers of total inflammatory and CD8 cells, and TIMP-1 concentration were significantly higher in patients with stage 2 disease in comparison with those in patients with stage 1 disease. There were significant correlations between %VC and the numbers of inflammatory cells and TIMP-1 in the BAL fluid. These results suggest that inflammation and enhanced TIMP-1 concentration in the lower airway play critical roles in the impaired pulmonary function in patients with lung parenchymal sarcoidosis.