The Histopathology of Labial Salivary Glands in Primary Sjögren’s Syndrome: Focusing on Follicular Helper T Cells in the Inflammatory Infiltrates
Figure 5
Graphical summary of ectopic lymphoid-like structure organization in exocrine tissue of patients with pSS. During the initiation phase of inflammation, activated T, B, and DC cells accumulate around ductal epithelial structures (a). Inflammatory responses, including chemokine signals by stromal cells can elicit the formation of more organized lymphoid structures (b) and (c). Aggregates with the highest organization level display separated T- and B-cell-rich areas with a central network of FDCs, which correspond to ectopic GCs (d). GC localized TFH cells are characterized by CXCR5, ICOS, PD-1, CD40L, and SLAM family members as CD84, SAP, and IL-21. The interplay between TFH and GC B cells is essential for the formation and maintenance of ectopic GCs, moreover for the generation of memory B cells and long-lived plasma cells. DC: dendritic cells; FDC: follicular dendritic cells; GC: germinal center; HEV: high endothelial venule; SAP: SLAM-associated protein.
