 Part B of the study will enroll SLE subjects with GN into Cohorts 4, 5, and 6 6 AMG 811: 2 placebo. Similar to Part A, subjects in Cohorts 4, 5, and 6 will be dosed every 4 weeks with AMG 811 or placebo for a total of 3 injections followed by a 5 month follow-up period. For Cohort 6, subjects will be followed by a 6 month follow-up period. 