Expression And Function Of IL-9 In Vogt-koyanagi-harada

OBJECTIVE This study was designed to investigate whether IL-9 plays a role in the development of Vogt-Koyanagi-Harada(VKH).METHODS The expression of IL-9m RNA in peripheral blood mononuclear cells(PBMC)was measured by Real-Time Polymerase Chain Reaction(RT-PCR).IL-9 in supernatants of cultured PBMC and CD4+T cells from patients with active or inactive VKH and healthy individuals was detected by enzyme-linked immunosorbent assay(ELISA).Interleukin-17(IL-17)and IFN-γ levels were detected with ELISA after PBMC and CD4+T cells were co-cultured with r IL-9.RESULTS VKH patients in active stage showed a significantly higher expression of IL-9 in the supernatants of stimulated PBMCs and CD4+T compared with those in inactive stage(P<0.01)and normal controls(P<0.01).IL-9m RNA of PBMC was significantly elevated in active VKH patients,compared with inactive VKH patients(P=0.018)and normal controls(P=0.040).r IL-9(500ng/ml)induced proliferation of PBMC from health controls(P=0.004)and VKH active patients(P=0.016).r IL-9(100ng/ml)didn’t induce significant proliferation of PBMC from health controls(P=0.051)and VKH active patients(P=0.322).Further studies of r IL-9(100ng/ml)on cell proliferation of PBMCs from three groups confirmed the same result: health controls(P=0.50),VKH active patients(P=0.08),VKH inactive patients(P=0.06).Thus,in this study,100ng/ml of r IL-9 was used in following researches.After PBMCs and CD4+T cells were stimulated with r IL-9(100ng/ml),the secretion of IL-17 increased.In PBMCs from health controls(P=0.01),in VKH active patients(P<0.01),in VKH inactive patients(P=0.02);In CD4+T cells,health controls(P=0.02);in VKH active patients(P<0.01),in VKH inactive patients(P=0.01).After stimulated with r IL-9(100ng/ml),the level of IFN-γ showed no significant change in PBMCs or CD4+T cells.In PBMCs,IFN-γ from health controls(P=0.71);in VKH active patients(P=0.40),in VKH inactive patients(P=0.49).In CD4+T cells,IFN-γ from health controls(P=0.77);in VKH active patients(P=0.63),in VKH inactive patients(P=0.68).CONCLUSIONS Expression of IL-9 was increased during the active phase of VKH.IL-9 induced PBMC proliferation when reaching the concentration of 500ng/m L.IL-9 may enhance the inflammation response by increasing the secretion of IL-17,an established pro-inflammatory cytokine in VKH.