HLA-DPB1 and synovial sarcoma: The associations of DRB1*08∶03 (Pc = 0.0001, OR 3.13, 95%CI 1.97–4.96), DQB1*06∶01 (Pc = 0.0173, OR 1.75, 95%CI 1.27–2.43), or DPB1*05∶01 (Pc = 0.0064, OR 1.59, 95%CI 1.23–2.05) with anti-Ro/SS-A antibodies remain significant after excluding RA patients with secondary SS.