Th2 lymphocytes producing IL-4, 5 play a crucial role in the pathogenesis of many allergic disorders. IL-4 plays an especially important role in differentiation of the Th2 phenotype. B7-2 (CD86) is reported to play a crucial role in differentiation of the Th2 phenotype. The effects of CD86 on IL-4 production remain unclear, however, in atopic diseases. We studied cytokine production profiles of by peripheral blood mononuclear cells (PBMCs) in Japanese cedar pollinosis (JCP) subjects after in

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... ro stimulation. PBMCs were isolated from 20 JCP and 12 control subjects and stimulated with Japanese cedar pollen extract. Th1 and Th2 cytokine production was measured by ELISA. The surface expression of IL-4 on CD4+ cells was assessed using flow cytometry in the presence or absence of anti-CD86 mAb. After in vitro stimulation, significantly higher levels of IL-5 were produced by PBMC of JCP subjects than controls (p=0.01). In contrast, significantly higher levels of IFN-y were produced by PBMCs of controls than JCP subjects (p=0.01). The surface expression of IL-4 on CD4+ cells was significantly upregulated following stimulation in JCP subjects compared to controls. The surface expression of IL-4 on CD4: cells was inhibited by anti-CD86 mAb. These results indicate that the Th2 response is predominant in JCP subjects after in vitro allergen stimulation and that IL-4 may function to some degree. CD86 may be costimulatory molecules in allergen-induced IL-4 production.