Quantitation of intraepithelial lymphocytes in human jejunum.

An estimate of the number of intraepithelial lymphocytes in jejunal villous epithelium can be obtained by differential counting of nuclei in the epithelium. From counts carried out in 160 jejunal biopsies from patients who did not have coeliac disease the normal range has been established as 6-40 intraepithelial lymphocytes per 100 villous epithelial cells. In some biopsies there was a moderate increase in the intraepithelial lymphocyte count; this was probably an objective measurement of ;increased chronic inflammatory cell infiltrate'. Intraepithelial lymphocyte counts were high in untreated coeliac disease; counts were lower, but rarely within the normal range, in coeliac patients on a gluten-free diet. Counts were normal in most autoimmune diseases, ulcerative colitis, and Crohn's disease. There were abnormal intraepithelial lymphocyte counts in four patients, with otherwise normal jejunal histology, in whom no cause had been found to explain prolonged and incapacitating gastrointestinal symptoms.