To our knowledge, the data presented here are the first to describe that treatment with the biological drug belimumab results in improvement of the atheroprotective properties of HDL in SLE patients Our cohort had a relatively high disease activity before treatment with belimumab and the HDL of patients displayed impaired cholesterol efflux and antioxidant capacity, as well as increased levels of SAA1 and lipid peroxidation products as compared with the HDL of controls. This evidence concerns the gene SAA1 and systemic lupus erythematosus.