Increased IL-7 Expression in Vogt-Koyanagi-Harada Disease

PURPOSE. IL-7/IL-7R has been found to be involved in the pathogenesis of several autoimmune diseases. This study was designed to investigate the potential role of IL-7/IL-7R in the pathogenesis of Vogt Koyanagi-Harada (VKH), an organ-specific autoimmune disease. METHODS. IL-7 was measured with an enzyme-linked immunosorbent assay (ELISA) in serum obtained from patients with active or inactive VKH and from healthy individuals. The expression of IL-7R was measured by flow cytometry (FCM). Cell proliferation was determined after exposure of peripheral blood mononuclear cells (PBMCs) and CD4(+) T cells to recombinant IL-7. The levels of IL-17 and IFN-gamma levels were detected by ELISA after these cells were cocultured with recombinant IL-7. The influence of recombinant IL-7 on the expansion of Th1 and Th17 cells was evaluated by using FCM. RESULTS. IL-7 was significantly increased in the serum of patients with active VKH compared with those with inactive VKH (P <0.001) and normal controls (P <0.001). However, there was no difference between VKH patients and normal controls in the expression of IL-7R alpha on CD4(+) T cells. Recombinant IL-7 induced significant cell proliferation and secretion of IL-17 and IFN-gamma by PBMCs and CD4(+) T cells. It furthermore promoted the expansion of both Th1 and Th17 cells. CONCLUSIONS. The findings suggest that IL-7 is involved in the pathogenesis of VKH disease. (Invest Ophthalmol Vis Sci. 2012;53:1012-1017) DOI:10.1167/iovs.11-8505