Both in the whole cohort and separately in patients with SLE, the levels of IFN-λ1 correlated with IL-17A and IL-23, and concentrations of the latter two correlated with each other (ρ = 0.41, ρ = 0.44, ρ = 0.38, p < 0.0001 for the whole cohort). Here, IFNL1 is linked to systemic lupus erythematosus.