A case of IgA nephropathy associated with silicosis]

A 51-year-old male who had been working as a building wrecker for 20 years, was admitted to our hospital in June 1999 for proteinuria and hematuria examination. He started this work in 1978. Twelve years later, severe coughing and bloody sputum began and he was diagnosed as having silicosis in 1995. Urinalysis on admission showed proteinuria(294 mg/day), microhematuria(20-30/hpf), RBC cast and granular cast. High serum IgA(770 mg/dl) and high serum interleukin-6(IL-6) (3,280 pg/dl) were found. A renal biopsy showed mild mesangial matrix expansion and mesangial cell proliferation with IgA deposition, which was diagnosed as IgA nephropathy. Chest X-rays showed multiple small nodular lesions on both lung fields indicating silicosis. In Nov. 1999, he resigned from his job as a building wrecker because of increasing coughing and bloody sputum associated with body weight loss. Within 3 months after stopping this work, coughing and bloody sputum disappeared and the abnormal urinalysis findings returned to normal. Serum IgA and serum IL-6 data improved to 462 mg/dl and 2.5 pg/dl, respectively. It is suggested that silicon exposure might be related to the pathogenesis of IgA nephropathy in this patient.