PRTN3 and rheumatoid arthritis: Risk factors for RA-ILD include age, RA duration and older age at disease onset, male sex, high levels of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (ACPA), cigarette smoking, elevated erythrocyte sedimentation rate (ESR), high disease activity (based on disease activity score 28- DAS28) and severity (worse functional status, presence of destructive changes and rheumatoid nodules) [12–15].