Bronchoalveolar lavage is a safe and simple technique to evaluate lung disease related to exposure to mineral dusts. The aim of this study was to characterize the lymphocyte subsets in bronchoalveolar lavage of patients with silicosis. Bronchoalveolar lavage was carried out in 26 workers with different forms of silicosis: simple form (n = 12), complicated (n = 13) and 1 patient with acute form of the disease. As a control group, 7 healthy individuals were included. Compared to the control group, silicotic patients showed intense pleocytosis constituted mainly by alveolar macrophages with slight lymphocytosis. Lymphocyte subsets present in the bronchoalveolar fluid (BAL) of normal individuals were mature lymphocytes with phenotype CD2+TCRab (87.3%) and only 2.9% were CD2+TCRgd. CD4/CD8 ratio was 1.8 with few (16%) immature double negative T cells subsets (CD4-CD8-). In contrast, silicotic patients showed reduction of the more mature lymphocyte subset CD2+CD4+, CD2+CD8+ and a great increase (47%) of immature (CD4-CD8-) T cell subsets. No increase in the NK (CD56+) cell population was observed. Biochemical analysis of protein contents and determination of the Ig/albumin ratio characterized local immunoglobulin production within the pulmonary microenvironment. Furthermore, lack of increase of plasma cells, as well as the maintenance of the percentage of B lymphocyte population (CD19+) in the BAL of silicotic patients, favors the hypothesis that the cells responsible for Ig production are possibly located in the interstitial space. Altogether the results suggest development of lymphopoiesis and tertiary lymphoid tissue within the pulmonary microenvironment during the clinical course of silicosis.

Keywords: bronchoalveolar lavage, lymphocyte subsets, silicosis, immunophenotyping

Objective: To evaluate the radiological characteristics of conglomerate masses using high-resolution computed tomography of the chest. Methods: From among the patients treated between 1986 and 2004 at the Antonio Pedro University Hospital, 75 patients with silicosis and massive fibrosis, most working in the field of sandblasting, were selected for study. These patients were submitted to a clinical evaluation, chest X-ray and high-resolution computed tomography of the chest. Results: In more than half of the patients with accelerated silicosis, the chest X-ray revealed large type B and C opacities, denoting the severity of the disease in those patients. In 1 case, a unilateral mass simulating lung cancer was observed. High-resolution computed tomography scans of the chest were acquired for 44 patients. In most cases (88.6%), the masses were located in the superior and posterior thirds of the lung. Common findings within the masses included air bronchograms (in 70.4%) and calcifications (in 63.6%). A history of tuberculosis was reported by 52% of the patients. Conclusion: In the vast majority of cases, the masses were bilateral, predominantly located in the superior and posterior regions of the lung, featuring air bronchograms and interposed calcifications. Concomitant calcification of the mediastinal and hilar lymph nodes was another common finding. Exposure to high concentrations of dust and having a history of tuberculosis were considered significant risk factors for the development of progressive massive fibrosis.

Keywords: Pulmonary fibrosis; Silicosis; Silicon dioxide; Occupational diseases; Environmental exposure;