Compared with RA without ILD patients, positive rheumatoid factor (RF) (OR = 1.72, 95% CI: 1.47–2.01; P < 0.00001) and positive anti-citrullinated protein antibodies (ACPA) (OR = 1.58, 95% CI: 1.31–1.90; P < 0.00001) increased the risk of RA-ILD. The gene discussed is PRTN3; the disease is rheumatoid arthritis.