CD40LG and rheumatoid arthritis: This miR-155-mediated mechanism is relevant also in B cells from synovial fluid of patients with RA after they were stimulated with CD40L, TNF superfamily member 13b (TNFSF13B, also known as BAFF), IL-21, and anti-IgM, suggesting that in this system depletion of miR-155 alone is not sufficient to reduce IgG antibodies [69].