The results of anti-HMGB1 ELISA showed the content of anti-HMGB1 autobodies in SS patients (9.96 ± 5.55 RU/ml) were significantly higher than those of the control group (4.9 ± 1.4 RU/ml) (Fig. 1a, Suppl Fig. 1). Here, HMGB1 is linked to synovial sarcoma.