TWEAK expression has been examined in clinical specimens and while there have been conflicting reports about TWEAK mRNA and protein levels in the peripheral blood mononuclear cells and serum of SLE patients (72–75), there have been consistent reports of elevated TWEAK levels in the kidney and urine of LN patients (73, 76–78). The gene discussed is TNFSF12; the disease is systemic lupus erythematosus.