Cross-reactivity between the pollens of Cupressus sempervirens (common cypress) and of Cryptomeria japonica (Japanese cedar).

A clinical and immunologic study was performed comparing a group of French patients allergic to the pollens of cypress (Cupressus sempervirens, which belongs to the Cupressaceae family) and a group of Japanese patients allergic to the pollens of Sugi (Cryptomeria japonica, which belongs to the Taxodiaceae family). By skin testing, RAST, and RAST inhibition, clear cross-reactivity was detected between the two pollens. No cross-reactivity was detected between the pollens of Cupressus sempervirens and Sugi and the Pinaceae family. In addition, one can speculate that an antigen in Cupressus sempervirens is cross-reactive with SBP, the major allergen of Sugi, suggesting that there is a closer relationship between the Taxodiaceae family and the Cupressaceae family than between these two families and the other families of the gymnosperms. This finding throws new light on the taxonomy of the gymnosperms.