Enzymes as occupational and environmental respiratory sensitisers.

A literature review shows that airborne enzymes occurring in the general environment and in purified form in industrial production have a high allergenic potential to the airways, causing rhinitis, conjunctivitis and asthma. It can be assumed that this also applies to the increasing number of enzymes manufactured by the cloning of fast-growing genetically engineered microorganisms. Cross-sectional studies demonstrate exposure-response relations for IgE-mediated sensitisation and airway disorders. Atopic individuals are more susceptible to enzyme allergy than non-atopic individuals. Skin prick testing and measurement of specific IgE antibodies have been shown to be useful diagnostic tools. Very high concentrations of proteases may lead to emphysema. There is also evidence for non-allergic airway inflammation by proteases, probably via protease-activated receptor-2 and intracellular Ca(2+) release. It is recommended that all enzymes be classified with the risk phrase R42 (may cause sensitisation by inhalation) and that their inhalative uptake be totally avoided.