ACPA SC was associated with RA complicated with ILD (8.6 ± 25.1 vs. 2.3 ± 3.4 U/ml, respectively, P = 0.0003), particularly NSIP (10.7 ± 31.5 U/ml, P = 0.0017). The gene discussed is PRTN3; the disease is rheumatoid arthritis.