Follicular dendritic cells
Disease processes that FDC may contribute include primary FDC-tumor, chronic inflammatory conditions, HIV-1 infection development, and neuroinvasive scrapie.
Follicular DCs are a non-migratory population found in primary and secondary follicles of the B cell areas of lymph nodes, spleen, and mucosa-associated lymphoid tissue (MALT).
They form a stable network due to intercellular connections between FDCs processes and intimate interaction with follicular B cells.
[8] Interaction between FDCs precursors and lymphoid cells mediated by TNF-a and lymphotoxin (LT) is crucial for normal FDC development and maintenance.
By secreting the bridging factor MFGE8, which crosslinks apoptotic cells and phagocytes, FDCs promote selective debris removal from the GC.
These findings suggest that FDC possibly protect organism against autoimmunity by the removal of potentially self-reactive debris from germinal centres.
They capture immune complexes in CR1/2-dependent way either directly from the lymph or from macrophages, and move to the lymphoid tissue, where they transfer complement opsonized antigen to the FDCs.
These sarcomas often involve lymphoid tissues, but in a number of cases the tumor has been found in the liver, bile duct, pancreas, thyroid, nasopharynx, palatum, submucosa of the stomach or the duodenum.
- Centrocytes are small to medium size with angulated, elongated, cleaved, or twisted nuclei.
- Centroblasts are larger cells containing vesicular nuclei with one to three basophilic nucleoli apposing the nuclear membrane.
- Follicular dendritic cells have round nuclei, centrally located nucleoli, bland and dispersed chromatin, and flattening of adjacent nuclear membrane.