[A VALIDATION STUDY OF THE IMPROVED PRODUCT FOR MEASURING JAPANESE CYPRESS POLLEN-SPECIFIC IgE (THERMO SCIENTIFIC ™ ImmunoCAP ™ ImmunoCAP JAPANESE CYPRESS POLLEN-SPECIFIC IgE)].

BACKGROUND: Japanese cypress pollen is a major causative allergen of seasonal allergic rhinitis in Japan. Although ImmunoCAP-specific immunoglobulin E (IgE) reagent Japanese cypress pollen has been widely used as a diagnostic aid, its sensitivity requires enhancement. This study evaluated an improved version of this reagent.

METHODS: Serum samples from 61 subjects who underwent Japanese cypress pollen exposure testing in an environmental challenge chamber in Chiba University were assessed using the conventional ImmunoCAPspecific IgE Japanese cypress pollen product and the improved product. In addition, specific IgE for Cha o 1 and Cha o 2, the primary allergen components of Japanese cypress pollen, was evaluated and their reactivity to specific IgE was compared between the conventional and improved products.

RESULTS: The antibody titer of the improved product was approximately 1.8-fold that of the conventional product. In addition, higher correlations with Cha o 1 and Cha o 2 were observed for the improved product than for the conventional product. The clinical sensitivity (≥class 2) in 56 exposure test-positive subjects was better for the improved product (80.4%) than for the conventional product (71.4%).

CONCLUSIONS: An improvement of the ImmunoCAP-specific IgE reagent Japanese cypress pollen resulted in enhanced Japanese cypress pollen-specific IgE sensitivity. The primary reason for this appeared to be an improved Cha o 1- and Cha o 2-specific IgE detectability.