Identification of metal sensitization in sarcoid-like metal-exposed patients by the MELISA® lymphocyte proliferation test — a pilot study

BACKGROUND: Pulmonary function is often affected by the inhalation of metal particles. The resulting pathology might trigger various lung diseases, e.g., parenchymal lung fibrosis and granulomatous lung disorders. We previously demonstrated that 6 % of tissue-proven sarcoid patients had a positive beryllium lymphocyte proliferation test (BeLPT), thus correcting the diagnosis to chronic beryllium disease. The aim of this study was to examine if MEmory Lymphocyte Immnuno Stimulation Assay (MELISA®), currently used for non-pulmonary diseases, can identify metals other than beryllium that can also trigger sensitization and induce granulomatous disease. METHODS: This pilot study included 13 sarcoid-like patients who underwent MELISA®. Eleven patients also underwent BeLPT. Biopsy samples were tested for metal content by scanning electron microscope. Eleven study patients had been exposed to metals at the workplace and 2 had silicone implants. RESULTS: Two patients who had undergone BeLPT were positive for beryllium. MELISA® detected 9 patients (9/13, 69 %) who were positive for at least one of the tested metals: 4 reacted positively to nickel, 4 to titanium, 2 to chromium, 2 to beryllium, 2 to silica, and one each to palladium, mercury and lead. CONCLUSION: It is proposed that MELISA® can be exploited to also identify specific sensitization in individuals exposed to inhaled particles from a variety of metals.