On applying the optimal cut-off of serum IL-27 level for predicting high activity, AAV patients with serum IL − 27 level ≥ 300.8 pg/mL had a significantly higher risk for having high disease activity than those with serum IL − 27 level < 300.8 pg/mL (relative risk 3.380, 95% confidence interval 1.223, 9.345, P = 0.016). This evidence concerns the gene IL27 and anti-neutrophil cytoplasmic antibody-associated vasculitis.