The aim of this study was to analyze the type of immune response (Th1, Th2) and protein composition of bronchoalveolar lavage (BAL) of patients with sarcoidosis, pulmonary fibrosis associated with systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF). Flow cytometry analysis of intracellular cytokines revealed different patterns: in IPF and SSc Th2 profiles were predominant, whereas in sarcoidosis Th1 prevailed. The proteomic analysis of BAL fluid (BALF) showed that there were quantitative differences between the three diseases. These were more evident between sarcoidosis and IPF, confirming our previous observations, whereas SSc had an intermediate profile between the two, however with some peculiarities. Comparison of BALF protein maps, constructed with the same quantity of total proteins, enabled us to identify the main profiles of the three diseases: an increase in plasma protein prevalent in sarcoidosis and also present in SSc, though for fewer proteins with respect to IPF and a greater abundance of low molecular weight proteins, mainly locally produced, in IPF. These findings are in line with the different pathogenesis of these diseases: IPF is considered a prevalently fibrotic disorder limited to the lung, with intense local production of functionally different proteins, whereas sarcoidosis and SSc are systemic immunoinflammatory diseases.

Oxygen-derived free radicals produced by phagocytes have been postulated to contribute to lung tissue damage occurring during diffuse lung diseases (DLD). The two-dimensional electrophoretic (2-DE) analysis of bronchoalveolar lavage (BAL) protein composition revealed different protein profiles in sarcoidosis (S), idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc) with a significant increase of low molecular weight proteins in IPF. Some of these proteins are involved in antioxidant processes. The aims of this report were to analyse the oxidative stress occurring in patients with DLD through determination of BAL protein carbonyl content and to identify target proteins of oxidation by a proteomic approach (2-DE combined with immunoblotting with specific antibodies for carbonyl groups). Carbonylated proteins detected by enzyme-linked immunosorbent assay (ELISA) were increased in BAL of patients with S, IPF and SSc compared to healthy controls with a significant difference for S and IPF. The proteomic approach to the analysis of BAL revealed that protein carbonylation was a process involving specific carbonylation-sensitive proteins and that in IPF a greater number of proteins target of oxidation were present. In conclusion, to our knowledge, this is the first report providing a database of proteins target of oxidation in BAL of patients with sarcoidosis, idiopathic pulmonary fibrosis and systemic sclerosis.

Background: Human chitotriosidase is a chitinase selectively expressed by activated macrophages. An increase in chitotriosidase activity was previously described by us in the serum and bronchoalveolar lavage of sarcoidosis patients. Objective: The aim of the present study was to analyze serum chitotriosidase activity in a larger number of sarcoidosis patients to verify the reported increase with respect to controls and to compare serum chitotriosidase levels in patients with sarcoidosis and tuberculosis, two granulomatous disorders of different etiology. Methods: Chitotriosidase activity was measured in the serum of 96 sarcoidosis patients, 15 pulmonary tuberculosis patients and 30 healthy controls. Results: We found significantly higher serum chitotriosidase activity in sarcoidosis patients than controls (p < 0.01) and in sarcoidosis patients than tuberculosis patients (p < 0.01), confirming a striking elevation of chitotriosidase activity (>10 times greater than normal) in pulmonary sarcoidosis patients. This is the first time that chitotriosidase activity has been analyzed in the serum of patients with pulmonary tuberculosis; it was found to be significantly lower than in sarcoidosis patients and not significantly greater than in controls. Conclusion: Although the mechanisms leading to the increase in chitotriosidase activity in sarcoidosis are still unknown, this enzyme may be specifically involved in the pathogenesis of the disease. Further studies with a greater number of patients are needed to confirm these results and to determine whether chitotriosidase could be a marker with diagnostic or prognostic value in sarcoidosis.

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In order to characterize BAL (bronchoalveolar lavage) in CEP (chronic eosinophilic pneumonia) and to investigate the possible role of mast cells and tryptase in the pathogenesis of this interstitial disease, cells and tryptase levels were determined in BAL of patients with CEP and in a group of healthy controls. The results show that a statistically significant increase in tryptase concentration was found in patients with CEP compared with the healthy controls. This is the first report that shows an increase in tryptase levels in CEP and could reflect higher mast cell activation as well as larger mast cell populations in the lungs of these patients. These results strongly support the involvement of mast cells and eosinophils in the immunopathogenesis of CEP.