Allergenic differences among pollens of three Salsola species.

BACKGROUND: Sensitivity to Chenopodiaceae is a frequent cause of allergic respiratory diseases in geographic areas where sensitization to Salsola kali and Chenopodium album has been reported. The objective of this study was to evaluate the pattern of sensitization to 3 Salsola species in patients residing on the Mediterranean coast of south-eastern Spain. METHODS: S. kali, S. vermiculata and S. oppositifolia pollen extracts were prepared. Patients reporting respiratory and/or cutaneous symptoms were skin prick tested with the 3 Salsola extracts. Individuals with positive skin prick tests to at least 1 of the 3 Salsola species were included. Specific IgE was determined by direct ELISA. SDS-PAGE and 2-D analysis were conducted to elucidate the protein profile. The allergenic profile was investigated by immunoblot. Inhibition experiments were conducted to establish cross-reactivity between different species. RESULTS: 246 patients were included. 237 patients (96.3%) tested positive to S. oppositifolia, 189 (76.8%) to S. kali and 185 (75.2%) to S. vermiculata. Protein profile and immunoblot demonstrated similar patterns in all extracts, except in low-molecular-weight allergens of S. oppositifolia. Immunoblot inhibition experiments demonstrated that most high-molecular-weight allergens of S. oppositifolia were inhibited by S. kali whereas low-molecular-weight allergens were totally inhibited only by C. album. CONCLUSIONS: This study confirms the allergenic importance of other Salsola species, especially S. oppositifolia. We have demonstrated that the 3 species show a high degree of cross-reactivity, but S. oppositifolia shares more allergenic similarities with C. album than S. kali.