Exposure to mushroom spores may causemany respiratory allergic diseases, however, there has been no
serial studyin amushroomfactory 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