['Osteopontin (OPN) is a proinflammatory cytokine involved in chronic inflammatory diseases. This study aimed to analyze the role of OPN in the pathogenesis of Vogt-Koyanagi-Harada (VKH) disease.', 'Serum levels of OPN in VKH patients and healthy controls were assayed by enzyme-linked immunosorbent assay (ELISA). Peripheral blood mononuclear cells (PBMCs) or CD4+ T cells were cultured with anti-CD3 and anti-CD28 antibodies in the absence or presence of recombinant OPN for the determination of cell proliferation and cytokines. Cell proliferation was detected using a cell counting kit. Levels of interferon (IFN)-γ and interleukin (IL)-17 were detected by ELISA. Four single nucleotide polymorphisms (SNPs) of OPN and four SNPs of OPN receptors were genotyped in 601 VKH patients and 605 healthy controls using a polymerase chain reaction-restriction fragment length polymorphism assay.', 'OPN serum levels were significantly higher in patients with active VKH than in patients with inactive VKH and in healthy controls. PBMCs or CD4+ T cells cultured with recombinant OPN induced a marked cell proliferation and profound secretion of IFN-γ and IL-17 from patients with active VKH. A significantly increased frequency of the OPN rs4754 TT genotype (P = 0.004, pc = 0.048) was observed in VKH patients compared with healthy controls. No association could be detected among the four selected SNPs of OPN receptors and VKH.'] Are elevated serum osteopontin levels and genetic polymorphisms of osteopontin associated with Vogt-Koyanagi-Harada disease?