LYMPHOCYTE SUBPOPULATIONS IN THE HUMAN SMALL-INTESTINE - THE FINDINGS IN NORMAL MUCOSA AND IN THE MUCOSA OF PATIENTS WITH ADULT CELIAC-DISEASE

Abstract

Lymphocyte subpopulations in human small intestinal mucosa were studied using an immunofluorescence technique on tissue sections. In the normal intestine, the majority of intraepithelial lymphocytes (IEL) were of suppressor-cytotoxic phenotype (HuTLA+ UCHTI+ OKT8+ OKT4-; 84%). Only 1/3 of these OKT8+IEL reacted with anti-Leu-1, and antibody directed towards a 67,000 dalton antigen found on peripheral blood T cells. IEL failed to express the activation antigen, Tac, and also lacked detectable C3b [complement component 3b] receptor (C3RTO5-). The remaining T IEL, and the predominant lamina propria T lymphocytes (LPL), were OKT4+ OKT8-, helper type T cells. Most of the lamina propria OKT8+ cells were also Leu-1-. In patients with adult celiac disease, the proportions of OKT8+ and OKT4- lymphocytes in the epithelium were not altered. The proportion of OKT8+ Leu-1+ T IEL was significantly increased (56 vs. 32%; P < 0.02). IEL were also HLA-DR-, Tac- and C3RTO5-. The proportion of OKT8+ cells in the lamina propria was slightly, but significantly, increased (40 vs. 32%; P < 0.005). Mucosal findings in treated patients did not differ from normal. Lymphocytes with the phenotype of natural killer cells (HNK-1) were rarely found in normal or diseased mucosa. No alterations in the proportions of circulating T lymphocytes or their subsets were found in patients with celiac disease. The findings illustrate the heterogeneity of lymphocyte subpopulations in normal and in diseased small intestinal mucosa. The changes found in adult celiac disease may reflect the increased traffic of IEL into the epithelium.