ABSTRACT
Alphitobius diaperinus is an important beetle in the grain and poultry industries. We evaluated three individuals with work-related symptoms of asthma, rhinitis, conjunctivitis, urticaria, and angioedema on exposure to the insect. Prick skin tests with extracts prepared from the larval, pupal, and adult life stages were positive in all three patients. Specific IgE antibodies to these extracts were demonstrated by RAST or radioimmunoassay. RAST and radioimmunoassay inhibition confirmed the specificity of IgE binding and further demonstrated immunologic cross-reactivity between the three life stages. Peripheral blood leukocytes from two of the individuals demonstrated significant histamine release when they were compared with cells from nonexposed atopic and normal control subjects. The proteins in the extracts of each life stage were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. More than 30 protein bands were detected in each of the extracts; however, the patterns of separation were different for each life stage. After immunoblotting and autoradiography, IgE-binding proteins were recognized by sera from all three individuals in the larval extract at 90 kilodaltons (kd), in the pupal extract at 90, 64, and 38 kd, and in the adult extract at 84 kd. Additionally, several other proteins were identified as being allergenic in some of the patients. We conclude that these three patients developed IgE-mediated sensitivity to A. diaperinus antigens as the result of occupational exposure. To our knowledge, this is the first description of sensitivity to this grain beetle.
