PDPN and Sjogren syndrome: found that during TLS formation in salivary glands in patients with Primary Sjogren’s Syndrome (pSS), the differentiation of a group of resident podoplanin (PDPN) positive mesenchymal cells into the “immunofibroblasts” that could support the early TLS formation happens before the infiltration of lymphocytes into the salivary glands, which is mainly regulated by IL-13 derived from resident ILCs and stromal cells (62).