Cry j 1-induced synthesis of interleukin-5 and interferon-gamma by peripheral blood mononuclear cells of patients with seasonal allergic rhinitis due to Japanese cedar pollens.

This study comprised 130 adult patients with Japanese cedar pollen-specific IgE in the serum and 15 non-atopic individuals. Eighteen patients had no seasonal aggravation of nasal symptoms during the pollen season in 1998 (asymptomatic group). Forty-two patients had not been treated previously with immunotherapy and were treated with antihistamine tablets during the pollen season in 1998 (medication group). Sixty-one patients had undergone variable periods of immunotherapy using pollen extracts, and they were further divided into a good-IT group who responded markedly to immunotherapy and a poor-IT group who responded poorly to immunotherapy. The remaining nine patients had been treated with immunotherapy for more than 12 years and all of them had stopped immunotherapy by the end of May 1997 because they had no nasal symptoms for the last three pollen seasons and were considered to be cured of seasonal allergic rhinitis (cure group). Peripheral blood mononuclear cells (PBMCs) were collected from each subject during the cedar pollen season in 1998 and were stimulated for 96 h with 10 micrograms/ml Cry j 1. The concentrations of interleukin-5 (IL-5) and interferon-gamma (IFN-gamma) in the culture supernatant were determined using an enzyme-linked immunosorbent assay. The levels of IFN-gamma did not differ significantly among the non-atopic group, the asymptomatic group, the medication group, the poor-IT group and the good-IT group. The level of IL-5 in the asymptomatic group was not different from that in the non-atopic group. The levels of IL-5 in the medication group, the good-IT group and the poor-IT group were significantly higher than in the non-atopic group. The level of IL-5 in the good-IT group, but not in the poor-IT group, was significantly lower than in the medication group. The level of IL-5 in the cure group was not significantly different from in the non-atopic group, and the level of IFN-gamma in the cure group was significantly lower than in the non-atopic group. In conclusion, immunotherapy can decrease the pollen allergen-induced synthesis of IL-5, but not of IFN-gamma, and this immunological modulation is involved in the working mechanism of immunotherapy related to its clinical efficacy. A tolerance or anergy of both TH1 and TH2 cells under allergen stimulation may be an immunological indication of cure after the treatment of seasonal allergic rhinitis. Thus, the suppression of synthesis of IL-5 and IFN-gamma by allergen-stimulated PBMCs is likely to be a reliable criterion for a possible cure of seasonal allergic rhinitis after immunotherapy.