Studies of intestinal lymphoid tissue. III. Quantitative analyses of epithelial lymphocytes in the small intestine of human control subjects and of patients with celiac sprue.

To investigate the morphology and proliferation of small intestinal lymphocytes, 1-micrometer sections of Epon-embedded jejunum from 14 control subjects and 5 celiac sprue patients were studied by light microscopy. Results showed that: (a) Epithelial lymphocytes were of significantly greater diameter in untreated, compared with treated, celiacs (P < 0.001), and comprised 5% more cells > 9 micrometer diameter compared with control mucosa. (b) Mitotic indices of epithelial lymphocytes were considerably raised in untreated sprue, and a brisk rate in accumulation of metaphase-arrests was observed during a 4-hr period of colchicine administration; after treatment, proliferative activity fell steeply, but not to the zero levels found in controls. (c) "Areal densities" (number of lymphocytes subtended by unit area of muscularis mucosae) were reduced in untreated patients (P < 0.02) and increased to control levels after treatment. "Flux ratios" (number of epithelial lymphocytes penetrating basal lamina/unit area muscularis divided by "areal density") were greater in untreated, than treated, specimens (P < 0.005) suggesting that in untreated sprue, there is increased traffic of lymphocytes across basal lamina. Thus celiac epithelium contains fewer, but significantly larger lymphocytes that exhibit heightened mitotic activity; greater numbers of lymphocytes also appear to be in transit across the basal lamina. With the exception of mitotic activity, all other observed changes were completely reversed by gluten withdrawal.