CTLA4 and systemic lupus erythematosus: Previous studies conducted in NZB/NZW F1 and related mouse models of lupus have led to the general conclusion that TACI‐Fc and BAFFR‐Fc were equally efficient to prevent lupus when administered as single agents before development of proteinuria, or to arrest or even reverse further disease development when administered together with CTLA4‐Fc, a T‐cell inhibitor, after onset of proteinuria 13, 28, 29, 30.