TNFSF13B and rheumatoid arthritis: While RA patients exhibit elevated BAFF-R expression in synovial tissue (Woo et al., 2011), BAFF is upregulated in several IMIDs including, IBD (Zhang et al., 2016), RA (Ohata et al., 2005; Woo et al., 2011), and SLE (Stohl et al., 2003).