Resumen de Follicular dendritic cells in normal and infected human appendix
Suganthy J. Rabi, lnbam Indrasingh
Follicular dendritic cells (FDCs) that reside within the lymphoid follicles play a central role in humoral immunity. They bind immune complexes and present antigen to follicular B cells and in the generation of B cell memory. This study aims to demonstrate the distribution of CD35 positive FDCs in normal and infected appendix by immunohistochemistry. Four normal and 5 infected appendix specimens were used for the study. Tissues collected were processed for immunohistochemistry, stained with mouse antihuman CD35 monoclonal antibody using the Polymer – HRP Detection System. Double immunostaining was done with mouse antihuman CD20 monoclonal antibody to find out the association CD35 positive Langerhans cells with B lymphocytes. Cells were viewed under the light microscope (Olympus DP21). In the normal appendix, CD35 positive FDCs were present in a reticular pattern in the germinal centre of the follicle. In acute appendicitis, the lymphatic follicles were not intact and FDCs were scattered in the mucosa of the appendix. Few discrete CD35 positive cells were seen surrounding the intestinal glands. CD20 positive B lymphocytes were noted in the lymphatic follicle, interfollicular areas, around the crypts and in the lamina propria. Apposition of CD35 and CD20 cells was noted. The dendrites of FDCs demonstrated in the follicles of appendix displayed an antigen-retaining reticulum which aids in trapping of immune complexes. Their association with CD20 positive B cells confirm the role of appendix in humoral immunity.
