Elevated serum IFN-λ1 levels in SLE patients with organ damage. (a) Serum IFN-λ1 levels exhibited a significant elevation in patients with renal involvement (n = 25) relative to patients without renal involvement (n = 17) as well as NC; patients in the absence of renal disorder also displayed higher serum IFN-λ1 levels compared with NC. (b) Serum IFN-λ1 levels were significantly higher in patients in the presence of arthritis (n = 29) than patients in the absence of arthritis (n = 13) as well as NC. Each symbol represents an individual patient; horizontal lines indicate median values. IFNλ1, interferon λ1; NC, normal control; SLE, systemic lupus erythematosus.