TLR9 and rheumatoid arthritis: The etiopathogenesis of most autoimmune diseases is still unclear, as several factors may contribute to their onset, such as the presence of autoantibodies, high serum levels of type I IFNs,150 or increased cell death, which trigger diseases such as RA and system lupus erythematosus (SLE).145 As the insufficient clearance of necrotic cells in RA and SLE results in the accumulation of nucleic‐acid containing material,151 researchers have investigated whether TLR9 is involved in these autoimmune responses.