A Chi2 test with MUC5B T-allele and RA-ILD defined as reticular opacities and/or honeycombing showed a prevalence of MUC5B of 43% in individuals with RA-ILD, whereas the prevalence was 20% in individuals without ILD, but the difference was not statistically significant (p 0.09) (Table 1). Here, MUC5B is linked to rheumatoid arthritis.