Elevated levels of tryptase in bronchoalveolar lavage fluid from patients with sarcoidosis.

Sarcoidosis affecting the lungs may cause obstructive and/or restrictive lung function impairment. The bronchial reactivity is related to the release of histamine from the mast cells. Upon activation mast cells also release tryptase. This enzyme may activate latent collagenase and thus possibly contribute to the fibrosis formation observed in sarcoidosis. We analyzed the bronchoalveolar lavage fluid (BALF) from 13 nonsmoking and untreated patients with sarcoidosis and from 30 healthy volunteers (18 smokers) with regard to the number of mast cells and the tryptase concentration. Concomitantly albumin, fibronectin and hyaluronan were measured as markers of the inflammatory reaction in the alveoli and interstitium. The number of mast cells was higher (p < 0.001) in patients with sarcoidosis than in controls. Also, the concentration of tryptase was significantly higher in patients (225.3 +/- 83.9 [SEM] mU/L) compared to nonsmoking and smoking controls (34.7 +/- 7.8 and 44.7 +/- 13.0 mU/L, respectively; p < 0.01 for both). In addition, the concentrations of albumin, fibronectin and hyaluronan were higher in patients with sarcoidosis compared to the nonsmoking controls (p < 0.001 for all). However, there was no relationship between either the mast cell number or the tryptase concentration and the lung function parameters (VC, TLC, FEV1, FEV%, DLCO). As our patients did not show any functional signs of bronchial obstruction (FEV1 91.7% +/- 13.3 [SD] and FEV% 99.5% +/- 6.4 of predicted) the lack of correlation is not surprising. The high concentrations observed in the BALF of the noncellular components may just reflect an ongoing inflammatory process that may resolve or, if exaggerated, lead to fibrosis.