Table 2.

Common HP-inducing antigens

Name of the Disease	Origin	Antigen	Source of Antigen
1. Farmer’s lung	Bacterial	Micropolyspora faeni, Thermoactinomyces vulgaris	Moldy hay
2. Summer-type HP	Fungal	Penicillium frequentans	Contaminated old houses
3. Hot tub lung	Mycobacterial	Mycobacterium avium complex (MAC), composed of M. avium and M. intracellularss	Contaminated water
4. Bird fancier’s lung	Animal fur protein	Avian proteins	Feather bloom, avian serum(pigeons, chicken, turkey, goose, avian proteins),and excrement (mainly due to pigeon intestinal mucin)
5. Chemical worker’s lung	Low-molecular weight chemicals	Diisocyanates, trimellitic anhydride	Polyurethane foams, spray paints, dyes, glues