SHORT REPORT Report of occupational asthma due to phytase and â-glucanase

Objectives—Occupational asthma is the principal cause of respiratory disease in the workplace. The enzymes phytase and â-glucanase are used in the agricultural industry to optimise the nutritional value of animal feeds. A relation between these enzymes and occupational asthma in a 43 year old man was suspected. Methods—Inhalation challenge tests were performed with the enzymes phytase, â-glucanase, and amylase. Skin prick tests were performed with the enzymes diluted to a concentration of 1 mg/ml and 5 mg/ml. Specific IgE to phytase and â-glucanase were measured with a radioallergosorbent test. Results—Baseline spirometry values were normal. A histamine challenge test showed bronchial hyperreactivity. Exposure to phytase and â-glucanase led to significant reductions in forced vital capacity and forced expired volume in 1 second. No significant diVerences were noted after exposure to amylase. Skin tests showed a positive reaction to â-glucanase (5 mm) at a concentration of 1 mg/ml and positive reactions to â-glucanase (7 mm) and phytase (5 mm) at a concentration of 5 mg/ml. Similarly specific IgE was present against both phytase and â-glucanase, at 2.5% and 9.3% binding respectively (2% binding is considered positive). Conclusions—This is the first description of occupational asthma due to the enzymes phytase and â-glucanase. Their addition to the ever increasing list of substances associated with occupational asthma will have notable implications for those exposed to these enzymes. (Occup Environ Med 2001;58:417–419)