In a retrospective study including 55 patients with Sjogren’s syndrome-onset SLE (SS/SLE), Yunjiao et al. revealed that these patients showed a significantly higher frequency of low complement levels (C3, 54.5% vs. 12.7%; C4, 41.8% vs. 7.3%, p = 0.000). Here, C4A is linked to synovial sarcoma.