Detection of specific IgE antibodies to Japanese cypress pollen in patients with nasal allergy: a comparative study with Japanese cedar.

Japanese cypress pollinosis has recently attracted attention and its clinical relationship with Japanese cedar pollinosis has been pointed out. To compare the two kinds of pollinosis, we retrospectively examined specific IgE antibodies to both pollen of Japanese cypress and cedar in the sera of 150 patients with nasal allergy using AlaSTAT assay. During the season in which the pollens of these two species are dispersed, the positive rates for Japanese cypress and cedar increased to 51.4 and 75.0%, respectively. The percentage of patients positive for both of cypress and cedar was elevated to 51.4%, corresponding to 68.5% of the total patient group positive for cedar. Almost all the cases positive for cypress had IgE antibodies to cedar, the value of which was considerably higher than that of cases positive only for cedar. Furthermore, increases in titers of specific IgE antibodies to cypress was observed in four of six cases, compared between specific IgE antibodies to cypress in pre- and post-dispersion of cypress pollen. These findings suggest the following possibility: (i) there is cross-antigenicity between the two pollen species, and (ii) patients are immunologically affected by cypress pollen to express higher levels of specific IgE antibodies after pollen dispersion.