Immunological and respiratory changes in tea workers.

Immunological status and respiratory function were studied in 26 female nonsmokers employed in processing different types of tea. Skin tests with tea-allergens demonstrated the highest percentage of positive reaction to sage (45%), gruzyan (40%), mentha (35%), and dog rose (10%). Among 17 skin-tested control workers, 23% had positive skin reaction to sage, 19% to gruzyan tea, 20% to mentha and 11% to dog rose and Indian teas. Serum levels of total IgE were increased in 27% of the tea workers and in 7% of the control subjects. Prevalence of almost all chronic respiratory symptoms was higher in tea workers with positive skin tests than in those with negative skin tests to tea allergens. Tea workers with positive skin tests to tea allergens had larger mean acute reduction over the Monday workshift in flow rates (MEF50%: -11.9%; MEF25%: -20.6%) than in those with negative skin tests (MEF50%: -5.7%; MEF25%: -16.7%), thus suggesting an obstructive effect mostly located in smaller airways. Bronchoprovocation testing with different tea allergens provoked acute reductions of ventilatory capacity in four out of six subjects tested. Relative fall over a 90-min post exposure was greater in MEF25% (ranging from 13% to 67%) than in MEF 50% (ranging from 9% to 45% of the control values).