It was found that the MUC5B promoter variant, elevated interleukin-17A receptor and citrullination in the lung tissue may contribute to the onset and progression of RA-ILD.7–9 It is also worth noting that apart from the natural course of RA and infection, disease-modifying antirheumatic drugs (DMARDs) may induce or worsen ILD.10 In this situation, making the decision with patients in therapeutic regimens is more complicated. The gene discussed is MUC5B; the disease is rheumatoid arthritis.