Specific IgE to Japanese cypress (Chamaecyparis obtusa) in patients with nasal allergy.

BACKGROUND

Japanese cedar (Cryptomeria japonica) is the most important pollen causing pollinois during spring. During recent years some patients' nasal symptoms have been getting worse after the Japanese cedar pollen season. Japanese cypress (Chamaecyparis obtusa) pollen is also observed in this period. The purpose of the study was to investigate the effect of Japanese cypress pollen and cross-allergenicity between Japanese cypress and Japanese cedar in patients with allergic rhinitis.

METHODS

A total of 267 patients were enrolled in the study. IgE antibodies to both tree pollens were measured by the CAP RAST method. The results of the CAP RAST test were compared with those of skin tests. In order to compare cross-allergenicity between these two pollens, CAP RAST inhibition assay was carried out.

RESULTS

The positive frequencies of Japanese cypress and Japanese cedar in 267 patients were 50.1% and 74.7%, respectively. A significant correlation (r = .765) was observed between the two tree pollens. There was good concordance (75%) between RAST and skin tests to Japanese cypress. The results of RAST inhibition assay indicated cross-allergenicity between these two pollens and species-specific allergens.

CONCLUSIONS

Measurement of IgE antibody to Japanese cypress is useful for the diagnosis of pollinois during the spring.