IFNL3 and systemic lupus erythematosus: As shown in Fig. 1, we found that the serum IFNL3 levels were significantly increased in SLE patients with high SLE disease activity index (SLEDAI > 4, N = 19; IFNL3 concentration 9.190 ± 1.351 pg/ml) as compared to the patients with low disease activity (SLEDAI ≤ 4, N = 51; IFNL3 concentration 3.413 ± 0.3171 pg/ml) (P < 0.0001).