SECRETORY IMMUNOGLOBULINS IN COLONIC NEOPLASMS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 85  (2) , 303-316
Abstract
Secretory immunoglobulins [Ig] are found in nongoblet columnar cells of normal intestinal epithelium. These molecules consist of a secretory component portion, which is synthesized in the columnar cells, and an Ig portion which enters the columnar cells from plasma cells in the adjacent lamina propria. The synthesis and transport of these various subunits were studied by immunofluorescence in [human] benign polyps and cancers of the colon. In the epithelium and plasma cells of benign and malignant tumors, and in normal tissue, IgA is the principal Ig, followed by IgM. When compared to normal tissue, neoplastic epithelium contains less Ig and less secretory component; the decrement usually inversely parallels the degree of differentiation. Benign polyps closely resemble normal colonic mucosa insofar as the secretory Ig system is concerned. Atypical areas of benign polyps and carcinomas exhibit greatly decreased or absent synthesis and transport of secretory IgA. Plasma cells tend to be markedly decreased in the stroma of carcinomas, suggestive of an alteration in the normal mechanism for attracting the circulating precursors of local IgA plasma cells. Whenever neoplastic epithelium contained IgA, plasma cells with IgA could be observed in the vicinity, in keeping with the concept of local synthesis of secretory IgA. In some instances in which local plasma cells were plentiful, neoplastic cells were deficient in secretory component and IgA, suggesting impairment of the mechanisms for transporting IgA across epithelium. The possible role of secretory component in such transport and in attracting lymphoblasts to mucous membranes is discussed.