Background: Japanese cedar (Cryptmeria japonica: CJ) pollinosis is one of the most important allergic diseases in Japan. Recently, the second major allergen (Cry j II) was isolated from CJ pollen. There have been no prevalence studies of sensitivity to Cry j I and Cry j II among a large number of patients with pollinosis.
Objective: This study was conducted to evaluate the prevalence of sensitivity to Cry j I and Cry j II. We measured specific IgE antibodies to these allergens in the sera of 145 patients. Furthermore, comparison of the sensitivity to Cry j I and Cry j II was examined by the histamine release assay.
Methods: Specific IgE antibodies to Cry j I and Cry j II were assayed by a fluorometric ELISA. Allergen-specific histamine release was measured by a radioimmunoassay kit.
Results: More than 90% of 145 patients had specific IgE antibodies to both allergens, the remainder had specific IgE to either one or the other. There were seasonal changes in the level of specific IgE. The changes in the levels of anti-Cry j II IgE antibodies were parallel to those of anti-Cry j I IgE. The histamine release assay with leucocytes from the patients demonstrated that the allergenic potency of the two allergens is almost the same.
Conclusion: Cry j II is an as important a major allergen as Cry j I.