Different allergenicity of pollen extracts of three Mediterranean cypress species accounted for cytological observations

BACKGROUND: Cypresses play an important role in the urban landscape of the Mediterranean region, releasing a huge amount of allergenic airborne pollen which causes a specific pollinosis in exposed people. OBJECTIVE: The aim of this work is to evaluate, in vivo and in vitro, the potential allergenicity of Cupressus macrocarpa pollen, and to compare it with the allergenicity observed for C. arizonica and C. sempervirens. METHODS: Pollen extracts of the three species were prepared, to determine their protein profile through SDS PAGE analysis and to evaluate their allergenic potential through EAST inhibition assays and SPT. Pollen grain composition was evaluated using a cytochemical approach with optical microscopy. RESULTS: SDS PAGE, EAST inhibition and SPT indicated the higher allergenic potential of C. arizonica compared to C. sempervirens and C. macrocarpa. No significant differences in allergenic potential were found between the latter two species. Cytochemical observations reveal higher ?-glucans and protein content in the intine of C. arizonica during hydration. CONCLUSION: The higher protein content found in C. arizonica pollen grains extract may be due to higher enzyme activity leading to the movement of ?-glucans and pectins from the intine to the partially developed pollen cell wall during hydration. This could explain the higher potential allergenicity of C.arizonica in respect to C. macrocarpa and C. sempervirens.