We next assessed the impact of neonatal viral infection on lupus-like manifestations in mice with various degrees of genetic susceptibility, including male BXSB mice with early-onset severe autoimmunity due to a Y chromosome-associated Tlr7 gene duplication [35, 36], female BXSB mice with late onset, low-incidence mild disease, and non-autoimmune C57BL/6 mice. This evidence concerns the gene TLR7 and systemic lupus erythematosus.