TNFSF13B and rheumatoid arthritis: These results are in keeping with previous reports [49], showing no difference in the expression patterns of BAFF between CD21+ and CD21− synovial tissues, but an up-regulation of APRIL mRNA in GC+ synovitis, and indicate that ectopic lymphoneogenesis in RA synovium develops and is maintained in the presence of high expression levels of these factors.