Mushroom worker's lung caused by spores of Hypsizigus marmoreus (Bunashimeji): elevated serum surfactant protein D levels.

This is a report on two patients with occupational hypersensitivity pneumonitis (HP) caused by spores of Hypsizigus marmoreus (Bunashimeji) and serial follow-up measurements of serum surfactant protein D (SP-D) levels. The diagnosis of HP was confirmed immunologically by the detection of serum precipitins to spores of Bunashimeji, but not to other antigens, and by the positive results of in vitro lymphocyte proliferative response for Bunashimeji antigens using BAL fluid lymphocytes. This is the first case report of HP caused by Bunashimeji. Serum SP-D levels for the two patients (493 and 226 ng/mL; cut off level, 110 ng/mL) were elevated at diagnosis and decreased after separation from antigens following corticosteroid therapy. However, in one patient who returned to the same job, the symptoms appeared again and SP-D level also increased.