BAFF-transgenic mice and mice with B cell-specific BTK overexpression (CD19-hBtk) develop autoimmune pathology resembling human systemic lupus erythematosus (SLE) and primary Sjögren’s syndrome (pSS; Thien et al., 2004; Kil et al., 2012). The gene discussed is CD19; the disease is systemic lupus erythematosus.