Additionally, SS NHL occurrence was associated with lymphopenia (28.3% vs 11.6%, P < 0.001), anemia (46.7% vs 23.9%, P < 0.001), RF positivity (85.4% vs 52.4%, P < 0.001), anti-Ro/SSA or/and anti-La/SSB positivity (91.2% vs 70.0%, P < 0.001), monoclonal gammopathy (23.3% vs 5.0%, P < 0.001), as well as cryoglobulinemia (32.1% vs 6.5%, P < 0.001) and low C4 complement levels (80.9% vs 48.1%, P < 0.001). The gene discussed is C4A; the disease is synovial sarcoma.