Immunoglobulin A: localization in rectal mucosal epithelial cells.

Immunofluorescence studies with monospecific antiserums to human serum immunoglobulins consistently revealed immunoglobulin A within the apical portion of the cytoplasm of rectal mucosal epithelial cells in normal subjects, as well as in patients with various bowel diseases. Immunoglobulins M, G, and D were not demonstrated within mucosal epithelial cells. The predominance of lymphoid cells containing immunoglobulin A in the lamina propria of intestinal tissues was confirmed.