In vitro corticosteroid sensitivity assay indicated that PHA-stimulated tumour necrosis factor-α (TNF-α), IL-12 and interferon-γ (IFN-γ) secretion was significantly inhibited by 10-6 M Dexamethasone in all controls and SS patients, compared with that in SR group, which confirms patient classification as SR and SS by disease activity index (SLEDAI) score. Here, IFNG is linked to synovial sarcoma.