Pearson correlation analysis revealed a positive correlation between serum IL-18 levels and BVAS scores (r = 0.56, P = 0.02 < 0.05) and ESR levels (r = 0.36, P = 0.04 < 0.05) in AAV patients. The gene discussed is IL18; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.