Hypersensitivity Pneumonitis Due to Mushroom (Pholiota nameko) Spores

Hypersensitivity Pneumonitis Due to Mushroom (Pholiota nameko) SporesHypersensitivity pneumonitis has been described in recent years as an occupational hazard of mushroom workers. Thermophilic fungi were thought to be responsible for hypersensitivity pneumonitis among mushroom workers. In this article, we demonstrate a hypersensitivity pneumonitis possibly due to the inhalation of the spores of the mushroom named Pholiota nameko.
Mushroom Cultivation Methods
The edible mushroom Pholiota nameko is cultivated indoors in all seasons in Japan. Wet wood dust is used instead of compost. In a small, windowless building which is kept at high temperature and humidity by air conditioner, many mushrooms grow on the surface of the package which consists of a mixture of the mushroom spawns and wood dust. When they are grown, the cultivating room is filled with the spores and/or oidiospores of the mushroom. Workers who harvest the mushroom easily inhale the spores. As the size of the spores are 4 to 6 p., they can reach the terminal areas of the lung. Workers in the building may also be exposed to other contaminants such as molds. These contaminants in this growing method are less than those in the outdoor method because compost is not used and molds do not grow as readily. www.cfp-for-you.com

Case Report
A 52-year old man started work in a mushroom-cultivating building which was mainly concerned with harvesting the P naineko mushroom. Seven years later, he noticed dry cough, dyspnea on exertion, and slight fever several hours after work. These symptoms became so marked that he required admission to a hospital for one month. At the end of this time, his condition had improved. However, on return to his former work, these symptoms appeared again. In October 1984, he visited our hospital. On admission, auscultation of his chest revealed slight crepitations in the lower parts. Chest roentgenogram demonstrated diffuse, fine, granular shadows on both lower lung fields. The BSR was slightly increased, and CRP was positive. Leukocytosis was not found. Mantoux reaction was negative. Pulmonary function studies showed a slight decrease of diffusion capacity. Histologic findings of the lung by transbronchial biopsy revealed granulomatous alveolitis compatible with that of hypersensitivity pneumonitis; thickening of alveoli due to infiltration of plasma cells, lymphocytes, giant cells, and infiltration of macrophage-like cells into the alveolar lumen. Manifest increase of lymphocytes was observed in the BALF; total cells were 2.5 X 107 82 percent of them were lymphocytes, 13 percent were macrophages, and others were neutrophilis and eosinophils. Pre-cipitins against the mushroom spore extract were detected, but not against Micropolyspora faeni.

Category: Pneumonitis

Tags: dyspnea cough, hypersensitivity pneumonitis, micropolyspora faeni