CXCL8 and thromboangiitis obliterans: The basal level of IL-6 in orbital fibroblasts from patietns with TAO (range: 405–3,195 pg/ml, mean: 1,794 pg/ml) and non-TAO (range: 0–2,807 pg/ml, mean: 925 pg/ml) patients varied depending on the strains of orbital fibroblasts (Fig 1), whereas IL-8 was not detected in non-treated orbital fibroblasts from either groups (Fig 2).