Distribution of Immunoglobulins in Human Rectal Mucosa

Abstract

Summary This study endeavored to identify and quantitate the major classes of immunoglobulins in rectal mucosal biopsies from 9 adults with quiescent or mildly active ulcerative colitis and 7 abnormal mucosal control subjects. Serial cryostat-cut tissue sections were stained with hematoxylin-eosin, methyl green-pyronin, and fluorescein-conjugated monospecific antisera to human serum immunoglobulins. As in normal and abnormal control subjects, IgA was demonstrated within the apical portion of the cytoplasm of rectal mucosal epithelial cells in all ulcerative colitis tissues. Although IgA cells predominated over IgM-, IgG-, and IgD-containing cells, the population density of IgA cells in the lamina propria of the rectal mucosa in ulcerative colitis was lower than in normal rectal tissues. Unlike control subjects, in ulcerative colitis IgA commonly was present in extracellular interstitial mucosal sites and IgA-containing cells were distributed irregularly and some fields showed very few IgA cells. The mean number of IgG cells per unit area of mucosal interstitium also was reduced in ulcerative colitis rectal tissues. The ulcerative colitis patients and the two control groups showed no staining differences for IgM and IgD.