<prompt> In the intra-epithelial region of the mucosa of intestine, the predominant cell population is that of -B cellT-cellsPlasma cellsBasophils  <response>: Around 15 of the cells in the small intestinal epithelium are lymphocytes. These Intraepithelial lymphocytes IEL are virtually all T lymphocytes but, unlike other T cells, most express the CD8 subset marker. The functions of this large population of T cells are unknown. 