Distribution of immunoglobulin producing cells is different in normal human appendix and colon mucosa.

Abstract

SUMMARY The densities of IgG-, IgA-, IgM-and IgD-producing immunocytes were determined by paired immunofluorescence staining and morphometric analysis in the lamina propria of normal appendix specimens. Normal colon specimens were used as reference material, mostly paired from individual subjects. The density (median of cells/mm2 lamina propria area) of IgA immunocytes tended to be slightly higher in the appendix than in the colon (1259 vs 962) and the same held true for IgM cells (71 vs 55). Conversely, the overall density of IgG immunocytes was much higher in the appendix than in the colon (95 vs 38). A striking feature was the fact that almost 50% of all immunocytes were of the IgG isotype adjacent to lymphoid follicles. It seemed justified to conclude, therefore, that the abundance of such follicles explains the overall enrichment of IgG-producing cells in normal appendix mucosa. These immunocytes most likely represent follicle derived B cells that have reached terminal maturation locally, whereas precursors generated from less mature memory clones probably emigrate and home ubiquitously to distant sites of the gut lamina propria where they develop into IgA-producing immunocytes.

Immunoreactivity against goblet cells in patients with inflammatory bowel disease

“…The appendix does also seem to be of central importance in the development of mucosal immune function, with a high proportion of immune cells of both T-and B-cell lineage. 42,43 An interesting epidemiologic study showed that removal of an inflamed appendix is protective for the development of UC but not of CD. 44,45 Appendectomy may reduce the exposure of goblet cell autoantigens for the immune system and hence reduce the risk of developing an immune reaction against goblet cells.…”

Discovery and Characterization of Secretory IgD in Rainbow Trout: Secretory IgD Is Produced through a Novel Splicing Mechanism

“…It has been found that secretory IgD cells in the peripheral blood are rare (∼3%), but make up a substantial population of the human respiratory tract mucosal B cells (17,29). In contrast to the upper respiratory tract, there are few IgD plasma cells in the digestive system mucosae, with only trace amounts of IgD in digestive fluids (30)(31)(32)(33). This indicates that IgD plasma cells are highly localized, and therefore may be related to the function of their secretory product.…”

Human appendix B cells naturally express receptors for and respond to interleukin 6 with selective IgA1 and IgA2 synthesis.

“…This population had the advantage of containing a high frequency of sIgA' B cells (20). Moreover, the appendix has been shown to exhibit features of GALT, and this includes a dome region covered by a unique epithelium containing follicle-associated or microfold cells, that function in the uptake of gut antigens for the induction of mucosal immune responses (21).…”