In summary, BAFF-RFP mice with either the Tlr7.1 Tg or Sle1 lupus genotype developed an autoimmune phenotype comparable to their parental line including higher systemic BAFF levels, expanded PCs in spleens and BMs, and increased anti-chromatin auto-Abs. This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.