Tnfsf4−/− mice were crossed with B6.Sle16 lupus-prone mice, which are characterised by development of humoral autoimmunity associated with splenomegaly, high level of total IgG and IgM, autoantibodies production and glomerulonephritis linked to Ig and C3 deposition in the kidney.31 32 The resultant B6.Sle16.Tnfsf4−/− female animals were monitored for 9 months (figure 4). The gene discussed is TNFSF4; the disease is Splenomegaly.