Clinical and immunologic studies among egg-processing workers with occupational asthma.
Twenty-five workers in an egg-processing factory were evaluated for respiratory sensitization to inhaled egg proteins by a physician evaluation, serial peak expiratory flow rate (PEFR) measurements for a 1-week period, and immunologic tests. Immunologic studies included skin prick tests, serum-specific IgE (RAST), and specific IgG (ELISA) to solutions prepared from commercial food allergens: factory-powdered egg white and yolk products and purified egg white fractions, including ovalbumin, ovomucoid, lysozyme, and conalbumin. Six workers had significant daily PEFR lability (greater than 20%) of whom five had associated cutaneous reactivity to at least one egg allergen. A diagnosis of "definite asthma" was established in five workers suspected by the physician of having asthma. These five workers exhibited significant decrements in daily PEFR that were accompanied by bronchial symptoms. Occupational asthma was diagnosed by the physician in four of the five latter workers. Definite asthma was significantly associated with both cutaneous reactivity to egg allergens (p less than 0.01) and RAST binding (p less than 0.01). Of eight workers with cutaneous reactivity to at least one egg reagent, four workers (50%) were positive to only purified egg white fractions. The highest levels of RAST binding were detected in four workers, and the best binding activity was to ovomucoid and ovalbumin fractions. Elevated specific IgG responses were significantly higher in egg-factory workers to whole egg (p less than 0.005), lysozyme (p less than 0.002), and conalbumin (p less than 0.002) allergens compared to responses of nonexposed control subjects. However, no differences in specific IgG were detected between symptomatic and asymptomatic workers.(ABSTRACT TRUNCATED AT 250 WORDS)