The role of cereal and fungal amylases in cereal flour hypersensitivity.

To investigate the role of cereal alpha and beta-amylase in bakers' asthma, we have compared the IgE response of 30 wheat-flour-allergic individuals to barley alpha and beta-amylases with that of fungal alpha-amylase using radioallergosorbent test (RAST), RAST inhibition assays and Western blotting. RAST analysis showed 29 of the 30 subjects with inhalant induced cereal allergy had positive IgE to cereal amylases, but only 16 were positive to fungal alpha-amylase. Regression analysis showed an association between specific IgE to wheat-flour and to barley alpha-amylase (r = 0.70) and barley beta-amylase (r = 0.92) but a poor association with fungal alpha-amylase (r = 0.34). RAST inhibition showed minimal crossreactivity between barley alpha or beta-amylase and barley and fungal alpha-amylase. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting showed that non-reduced barley alpha-amylase had a molecular weight of 54 kDa and barley beta-amylase a molecular weight of 64 kDa. Reduced fungal alpha-amylase had a molecular weight of 54 kDa. Cereal alpha and beta-amylase appear to be important allergens in patients with allergy to flour.