Cry j 1-induced synthesis of interleukin-5 and interferon-gamma by peripheral blood mononuclear cells of patients with seasonal allergic rhinitis dueto 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 s easonal aggravation of nasal symptoms during the pollen season in 1998 (asy mptomatic group). Forty-two patients had not been treated previously with i mmunotherapy and were treated with antihistamine tablets during the pollen season in 1998 (medication group). Sixty-one patients had undergone variabl e periods of immunotherapy using pollen extracts, and they were further div ided into a good-IT group who responded markedly to immunotherapy and a poo r-IT group who responded poorly to immunotherapy. The remaining nine patien ts had been treated with immunotherapy For more than 12 years and all of th em had stopped immunotherapy by the end of May 1997 because they had no nas al symptoms for the last three pollen seasons and were considered to be cur ed of seasonal allergic rhinitis (cure group). Peripheral blood mononuclear cells (PBMCs) were collected from each subject during the cedar pollen sea son in 1998 and were stimulated for 96 h with 10 mu g/ml Cry j 1. The conce ntrations of interleukin-5 (IL-5) and interferon-gamma (IFN-gamma) in the c ulture supernatant were determined using an enzyme-linked immunosorbent ass ay. The levels of IFN-gamma did not differ significantly among the non-atop ic group, the asymptomatic group, the medication group, the poor-IT group a nd the good-IT group. The level of IL-5 in the asymptomatic group was nor d ifferent from that in the non-atopic group. The levels of IL-5 in the medic ation group, the good-IT group and the poor-IT group were significantly hig her than in the non-atopic group. The le el of 1L-5 in the good-IT group, b ut 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, immun otherapy can decrease the pollen allergen-induced synthesis of IL-5, but no t of IFN-V and this immunological modulation is involved in the working mec hanism of immunotherapy related to its clinical efficacy. A tolerance or an ergy of both TH1 and TH2 cells under allergen stimulation may be an immunol ogical indication of cure after the treatment of seasonal allergic rhinitis . Thus, the suppression of synthesis of IL-5 and IFN-gamma by allergen-stim ulated PBMCs is likely to be a reliable criterion for a possible cure of se asonal allergic rhinitis after immunotherapy.