A cross-sectional survey of sensitization to Aspergillus oryzae-derived lactase in pharmaceutical workers

Background: The presence of IgE-mediated occupational respiratory sensitiza tion to microbial enzymes has been wed documented in a variety of industrie s. Aspergillus oryzae-derived lactase is used as a dietary aid for patients with lactose intolerance. Objective: In 1993, a cross-sectional survey of 94 pharmaceutical workers e xposed to lactase for a mean duration of 23 months and 24 nonexposed recent ly hired employees was initiated to identify lactase-sensitized workers and potential risk factors that could be used in making recommendations for pr eventing future cases of lactase sensitization. Methods: The survey included a physician-administered questionnaire, skin p rick testing to lactase enzyme and a panel of common aeroallergens, and spi rometry. Results: Twenty-seven of 94 lactase-exposed workers (29%) had positive skin test responses to lactase. These workers were 9 times more likely to have upper or lower respiratory symptoms compared with workers with negative ski n test responses. Atopic workers were 4 times more likely to have lactase s kin sensitivity than nonatopic workers. However, atopy was not a risk facto r for the development of upper and/or lower respiratory symptoms. Lactase s kin reactivity was not observed in the 24 nonexposed employees. Conclusion: This cross-sectional survey revealed that atopic workers were m ore likely to have lactase sensitization and that lactase-sensitized worker s were more likely to have upper and/or lower respiratory symptoms, but ato py was not a risk factor for upper or lower respiratory symptoms. In spite of these findings, the company allowed only nonatopic, nonlactase-sensitize d workers to continue working in high Lactase-exposure areas with careful s ymptom monitoring and use of protective clothing. Although this strategy wa s successful in total prevention of new cases of occupational respiratory d isease after 5 years, the results of this cross-sectional survey do not sup port exclusion of atopic workers from working with industrial enzymes.