Lymphoid cell subsets in normal human small intestine.

UNLABELLED

Nineteen specimens of normal tissue were obtained from the duodenum, upper jejunum and terminal ileum. Specimens were fixed with periodate-lysine-paraformaldehyde and then frozen sections were made. Lymphoid cell subsets were identified by indirect immunoperoxidase staining using mouse anti-human monoclonal antibodies.

RESULTS

There was a remarkable variation in the distribution of positive cells among individuals and even within single sections. Lymphoid cell subsets of the three parts of the small intestine were almost identical except for the difference in IgA subclasses of IgA-containing cells. IgA1 predominated over IgA2 in the jejunum while IgA2 predominated over IgA1 in the ileum. The subsets in the lamina propria (LP) and in the epithelium were clearly distinct; Leu 3+ (helper/inducer T) predominated in LP while Leu 2+ (suppressor/cytotoxic T) predominated in the epithelium and no Ig-containing cells were found in the epithelium. In LP the mean ratio of Leu 1+ (pan T):IgA (IgA1 + IgA2) containing cells: IgM: IgG: IgD: IgE: HNK-1+ was 48.9: 36.6: 9.0: 1.8: 1.0: 0.3: 2.4. The staining patterns of HLA-DR+ and Leu 10+ were similar; dense in the top in LP of the villi. In some individuals the apical portion of epithelial cells was stained by anti-HLA-DR. A few positive cells were observed in only two out of 19 cases by anti IL-2R.