Report of occupational asthma due to phytase and beta-glucanase.
OBJECTIVE
Occupational asthma is the principal cause of respiratory disease in the workplace. The enzymes phytase and beta-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, beta-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 beta-glucanase were measured with a radioallergosorbent test.


RESULTS
Baseline spirometry values were normal. A histamine challenge test showed bronchial hyperreactivity. Exposure to phytase and beta-glucanase led to significant reductions in forced vital capacity and forced expired volume in 1 second. No significant differences were noted after exposure to amylase. Skin tests showed a positive reaction to beta-glucanase (5 mm) at a concentration of 1 mg/ml and positive reactions to beta-glucanase (7 mm) and phytase (5 mm) at a concentration of 5 mg/ml. Similarly specific IgE was present against both phytase and beta-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 beta-glucanase. Their addition to the ever increasing list of substances associated with occupational asthma will have notable implications for those exposed to these enzymes.
O'Connor
T M
TM
Department of Respiratory Medicine, Mercy Hospital, Cork, Ireland. terryoconnor@eircom.net
Bourke
J F
JF
Jones
M
M
Brennan
N
N
D010832:6-Phytase / Q000009:adverse effects*; D000328:Adult; D000821:Animal Feed; D001249:Asthma / Q000139:chemically induced*; D001985:Bronchial Provocation Tests; D002480:Cellulase / Q000009:adverse effects*; D005503:Food Additives / Q000009:adverse effects; D006801:Humans; D008297:Male; D009784:Occupational Diseases / Q000139:chemically induced*; D012882:Skin Tests
D005503:Food Additives; D010832:6-Phytase; D002480:Cellulase