The CA19-9 level were weakly correlated with the ESR (r = 0.199, p = 0.008), but we found no correlations between KL-6 and disease activity indicators (p > 0.05), suggesting that KL-6 and CA19-9 might be involved in the pathogenesis of ILD rather than RA. The gene discussed is MUC1; the disease is interstitial lung disease.