Accelerated silicosis with mixed-dust pneumoconiosis in a hard-metal grinder

We describe a fatal case of accelerated silicosis with a component of mixed-dust pneumoconiosis in a young hard-metal grinder that we believe is the first case of its kind in Israel and one of the rare cases reported worldwide. The patient's diagnosis was based on typical features: restrictive lung function, abnormal chest roentgenogram suggesting lung fibrosis, a history of exposure to silica and hard metals, bronchoalveolar lavage (BAL) fluid findings, and mineralogical studies. BAL cells showed an abundance of giant multinucleated macrophages. The CD4/CD8 ratio of T lymphocytes was 1.1, with a high percentage of CD8 and CD8/38 positive cells (37% suppressor/cytotoxic and 12% cytotoxic T lymphocytes, respectively). mRNA transcripts isolated from BAL cells were positive for interleukin-1 (IL-1) and transforming growth factor (TGF) Il-5, IL-2, and IL-10 but not for IL-6, IL-4, and interferon. Polarizing light microscopic studies of BAL and induced sputum cells showed polarizing particles, which are typical for silica. Mineralogical studies of electron microscopy performed on BAL fluid and on dust collected at the patient's workstation revealed silica particles as well as aluminum-titanium and other particles. The latter might have contributed to the patient's lung disease.