Exposure to mushroom spores may causemany respiratory allergic diseases, however, there has been no
serial studyin a mushroom factory to address thisproblem.The aimofthis studywas toinvestigate the serial changes in
respiratory allergy and the incidence of hypersensitivity pneumonitis (HP) inmushroomworkers. A 3-year follow-up
study, beginningin June1996, was conductedin a newly operatingmushroomfactoryinwhich one kind ofmushroomis
produced: Hypsizigus marmoreus (Bunashimeji). Allergic symptoms, chest roentgenogram, serum precipitins to the
spores and soluble adhesionmolecules in serawere evaluated once a year in 60 workers and 20 controls.Three out of
the 60 subjectswere diagnosed as havingHPcaused byinhalation of themushroomspore and theywere therefore ex-
cluded fromthis study, and the 57 non-HP subjectswere evaluated. Inthis study 24workers quit because of intolerable
cough, runnynose,wheezing, sputum, feverelevationand/or shortnessof breathattheirplaceofwork.Duringeachyear
ofthis studyasmanyas 70^80%ofemployeessu¡eredsomeofthe above symptoms, coughbeingthemostfrequent, and
positive rate of serumprecipitins to the spore revealed 30% in1996,93% in1997 and 94% in1998. Fromthe June 1996
examination until the following May, serumsoluble intercellular adhesionmolecule-1 levels of the 15 workerswho quit
during that periodwere signi¢cantly higher than those in the 42 workers still employed in1997 (Po0?05).Workers in
Bunashimejimushroomfactoriesmight be at criticalriskof developingrespiratory allergy. In our 3-year study, over 90%
workerswere sensitized to the spore,40% quit because of the symptoms and 5% developed HP. It was suggested that
workers should be counselled about the risk of mushroom allergy and precautionary measures should be taken to
prevent its occurrence