The major findings of this study are as follows: Treatment with a PEGylated leptin antagonist (1) increases food intake and prevents cachexia in SLE mice, (2) decreases DN T cells in the circulation and increases the CD4/CD8 ratio, (3) lowers blood pressure, and (4) decreases renal glomerular injury and renal immune cell infiltration. This evidence concerns the gene LEP and systemic lupus erythematosus.