Besides, an Egypt study of patients with RA-ILD demonstrated that serum KL-6 was positively correlated with HRCT scores and lung ultrasound (LUS) scores (r = 0.93, r = 0.97, respectively), and pointed increased serum KL-6 combined with LUS is an importantly new and potential prognostic factor predicting poor outcomes in RA-ILD (12). Here, MUC1 is linked to rheumatoid arthritis.