TNFSF13B and rheumatoid arthritis: Specifically, BAFF expression has been observed in salivary gland epithelial cells in Sjogren’s syndrome, fibroblast-like synoviocytes in the synovium of patients with rheumatoid arthritis, osteoclasts in patients with multiple myeloma, astrocytes in patients with multiple sclerosis and in gut lavage fluid of patients with food hypersensitivity [40,41,42,43,44].