This study will be a multicenter, randomized, double-blind, placebo-controlled, multiple dose study in which approximately 24 subjects with SCLE will be enrolled. Cohort 1 will consist of 12 subjects (6 AMG 557: 6 placebo) randomized to receive AMG 557 210 mg or matching placebo. Cohort 2 will consist of 12 subjects (6 AMG 557: 6 placebo) randomized to receive AMG 557 140 mg or matching placebo. Enrollment of Cohort 2 (140 mg) will be initiated after enrollment of Cohort 1 (210 mg) is completed.