Rye flour allergens: An emerging role in baker's asthma

Abstract

Exposure to wheat flour is usually considered the most important cause of baker's asthma. However, other flours frequently used in bakeries may play an emerging role as relevant allergens causing occupational asthma. We report on two cases of baker's asthma mainly caused by exposure to rye flour. The profile of allergen sensitization to cereal flour was investigated. Two bakery workers suffering from rhinoconjunctivitis and asthma symptoms at work underwent an in vivo study (skin prick tests and bronchial allergen challenge) and in vitro study (total serum IgE, specific serum IgE and immunoblotting). Specific inhalation challenge with wheat flour did not elicit an asthmatic reaction, however both patients showed an early asthmatic reaction with the rye flour challenge. Rye flour-immunoblotting showed IgE-binding bands around 12-15 kDa, that correspond to rye flour enzymatic inhibitors which were not present in the wheat flour immunoblot. Both bakers had developed occupational asthma to rye flour (confirmed by specific inhalation challenge test). Rye flour allergens (enzymatic inhibitors) are important allergens that should be considered in the diagnosis of baker's asthma.