Correlational analysis showed that serum PCSK9 levels correlated with (A) age, (B) CRP levels and (C) ESR in SLE patients. SLE, systemic lupus erythematosus; LN, lupus nephritis; PCSK9, proprotein convertase subtilisin/kexin type 9; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate.