Allergic reactions to enzymes used in plant cloning experiments

We report a case of rhinitis and asthma resulting from exposure to enzymes used in an experimental plant pathology laboratory. Immediate skin-test responses were elicited to both "Cellulase" and "Macerozyme" products, and a large late onset skin reaction occurred at the Cellulase site beginning in 6 hr. Special radioallergosorbent test (RAST) substrates were prepared that showed a strong positive response to Cellulase. By the RAST method other laboratory workers were screened and another symptomatic individual was found who also showed evidence of type I hypersensitivity to both enzymes. Skin biopsy and immunodiffusion data are presented. We conclude that enzymes used to digest cell wall structures of plants are capable of eliciting both immediate and late onset skin-test reactions and positive RAST responses in susceptible persons. These reactions are thought to be mediated by IgE antibodies and can be associated with symptoms of rhinitis and asthma.