The purpose of this study is to determine how the body absorbs and chemically changes a single infusion of TRU-015 in subjects with kidney disease caused by lupus.

Inclusion Criteria:

• Man or nonlactating and nonpregnant woman, aged 18 to 70 years, inclusive, at the screening visit.
• Diagnosis of systemic lupus erythematosus more than 6 months before study day 1.
• History of positive antinuclear antibody titer of >1:160 or equivalent.
• Biopsy-proven class V lupus nephritis within the last 2 years.
• Have been on a stable dose of oral corticosteroids (<20 mg/day prednisone or equivalent) for 2 months before study day 1.