Seasonal increase in specific IgE in serum induced by natural Japanese cedar pollen exposure in asymptomatic and symptomatic sensitized individuals.

The aim of this study was to determine whether there is a difference in the specific IgE response to pollen exposure between asymptomatic and symptomatic subjects who were already sensitized to Japanese cedar pollen. Sixty-four subjects with detectable serum levels of cedar pollen-specific IgE, which were apparent even before the pollen season in 1997, were enrolled in the study. Thirty-five had typical symptoms of seasonal allergic rhinitis during the pollen season in 1997 (symptomatic group) and the remainder had no seasonal aggravation during the pollen season in 1997 (asymptomatic group). Serum samples were collected twice from each subject, before and during the pollen season in 1997, to determine specific IgE by the lumiward immunoassay system. In both groups, the serum levels of specific IgE during the pollen season were significantly higher than those before the pollen season, and the rates of seasonal increase in specific IgE did not differ significantly between the groups. In conclusion, the specific IgE response during the pollen season is not a hallmark of clinical allergy and does not discriminate between symptomatic and asymptomatic individuals sensitive to the pollen.