METTL3 and rheumatoid arthritis: Wang J et al. (2019) found that in patients with rheumatoid arthritis, METTL3 in macrophages is obviously improved and positively associated with CRP and ESR. Moreover, lipopolysaccharide (LPS) can stimulate the expression of METTL3 in macrophages and then slack the immune response to inflammation through NF-κB pathway (Wang J et al., 2019). Other autoimmune diseases such as osteoarthritis (Liu Q et al., 2019) and SLE (Li et al., 2018) show possibility of having connection with m6A dysfunction in macrophages.