2001 Volume 94 Issue 1 Pages 83-95
This study was designed to investigate the effect of a single year of immunotherapy on cytokine synthesis by allergen-stimulated peripheral blood mononuclear cells (PBMCs) of patients with seasonal allergic rhinitis. This study included 12 nonatopic subjects (nonatopic group) and 28 patients with seasonal allergic rhinitis due to Japanese cedar pollen. Immediately after the pollen season 1998, 14 patients started receiving immunotherapy (immunotherapy group), and the remaining were treated with antihistamines during the pollen season 1999 (medication group). PBMCs (1.0×106 cells/mL) were obtained from each subject before and during the pollen season 1999, and cultured for 96 hours in the absence of and in the presence of 10μg/mL of Cry j 1. The levels of IL-4, IL-5 and IFN-γ in the supernatants were determined using enzyme-linked immunosorbent assay (ELISA). Seasonal increase in Cry j 1-specific IL-4 and IL-5 synthesis was significant in the medication group and in the immunotherapy group, but not in the nonatopic group. Although the levels of Cry j 1-dependent IL-4 and IL-5 before the pollen season did not differ significantly between the untreated group and the immunotherapy group, the levels of Cry j 1-dependent IL-4 and IL-5 during the pollen season were significantly lower in the immunotherapy group than in the untreated group. The levels of Cry j 1-dependent IL-4 before as well as during the pollen season did not differed significantly between the good and poor responders to immunotherapy, whereas the levels of Cry j 1-dependent IL-5 during the pollen season were significantly lower in the good responders than in the poor responders to immunotherapy. Therefore, we concluded that the suppression of Cry j 1-dependent IL-5-producing Th2 cells during the pollen season is a major working mechanism of a single year of immunotherapy for seasonal allergic rhinitis due to Japanese cedar pollen.
