Induced sputum as an additional tool in the identification of metal-induced sarcoid-like reaction

Aluminium dust exposure produces asthma, chronic bronchitis, pulmonary fibrosis and granulomatous lung diseases. There is an increased risk of mistaken diagnosis of sarcoidosis when other interstitial lung diseases of known origin are occurring.

We describe a case of a welder working in a stainless steel factory who had been exposed for more than 20 years to a dusty environment containing high levels of hazardous dust. He underwent lung function studies, a beryllium-lymphocyte transformation test (BeLTT), induced sputum (IS) analysis, aluminum-induced blastic proliferation test, and mineralogical and immunologic studies. The lung function tests raised the suspicion of sarcoidosis. T cell subsets recovered from induced sputum disclosed a helper T lymphocyte alveolitis, and transbronchial biopsies showed sarcoid-like epithelioid granulomata. Peripheral blood lymphocytes exhibited blastic transformation in the presence of soluble aluminium compounds. Scanning electron microscope studies from induced sputum-retrieved material showed abundant particles of aluminum. His final diagnosis was sarcoid-like granulomatous-induced aluminium disease.

We propose an alternative non-invasive approach to identify antigenic metals in occupational exposures.