Identification of a 46-kD latex protein allergen in health care workers

Latex allergy is an occupational hazard for health care workers. Extractable latex proteins are known to be allergenic, but most latex allergens have not been specifically identified. The purpose of this study was to characterize the IgE response of latex-allergic patients to latex proteins and to identify common protein allergens. Serum was obtained from 40 individuals who were skin test-positive to latex; 85% were health care workers. Western blots for IgE reactivity were performed using both ammoniated (AL) and non-ammoniated (NAL) latex proteins and IgE-reactive NAL proteins were analysed by microsequence analysis. The patients were grouped according to common patterns of reactivity. Pattern 1, the most common pattern of reactivity (9/40 patients) recognized two protein bands in both NAL and AL at 46 and 110 kD. A second, heterogeneous pattern of reactivity (pattern 2) recognized a diffuse pattern of polypeptides in the AL preparation. The n-terminal amino acid sequences for allergens at 14, 18, 29, 46 and 110 kD were determined. Sequence analysis identified the 14-kD and 18-kD allergens as the hevein proprotein. The 46-kD and 110-kD had identical sequences which were unique from known latex proteins. We conclude that multiple latex proteins are allergens with hevein preprotein and a previously unidentified 46/110-kD protein being commonly recognized in health care workers.