PCSK9 and systemic lupus erythematosus: Indeed, while one study demonstrated a significant upregulation of plasma PCSK9 in a cohort of 90 young SLE patients [25], especially in the subgroup with accelerated atherosclerosis and lupus nephritis, other studies have reported either reduced or comparable plasma PCSK9 levels in other SLE cohorts [26,27] or in RA [28], and systemic sclerosis (SSc) patients as compared to HCs [29].