Background: Acalypha wilkesiana, or copperleaf, is a plant of the Euphorbiaceae family. Although it is widely known as an outdoor ornamental plant, no cases of A. wilkesiana allergy have been reported to date.
Objective: To describe a patient with occupational respiratory allergy to A. wilkesiana.
Methods: Extracts from A. wilkesiana leaves and flowers were used for skin prick testing, specific conjunctival and bronchial challenge tests, and in vitro studies. These studies range from A. wilkesiana specific IgE determination to sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunodetection of A. wilkesiana protein bands in patient serum samples and immunoblot inhibition by preincubation with Salsola kali and Chenopodium album pollen extracts.
Results: Our patient had positive skin prick test reactions to A. wilkesiana leaf and flower extracts; negative reactions were found in a control group of 20 atopic patients. On immunodetection of A. wilkesiana extracts in patient serum samples, as many as 9 different IgE-binding proteins, with apparent molecular weights of 16 to 86 kDa, were revealed. Preincubation with S. kali and C. album pollen extracts completely inhibited IgE binding to the A. wilkesiana extract. Specific bronchial challenge resulted in a spirometric 30% decline in forced expiratory volume in 1 second with respect to baseline 1 minute after 1:100 (vol/vol) A. wilkesiana extract solution inhalation; 2 atopic controls had negative bronchial challenge test results.
Conclusion: Acalypha wilkesiana is a new etiologic agent for IgE-mediated occupational respiratory allergy.