Characterization of the inflammatory cell populations in normal colon and colonic carcinomas.

UNLABELLED: Little is known about the nature of the mucosa-associated immune system within the normal colon, or about the immune response to colon carcinoma. In this study inflammatory cells (ICs) in 14 normal colons and 14 carcinomas were characterized. Overall inflammation, lymphocytes, plasma cells, neutrophils, and eosinophils were graded in routine H & E sections. Frozen sections were stained by an immunoperoxidase technique using antibodies to the T cell associated antigens CD2, CD7, CD4, CD8, and T cell receptors alpha beta and gamma delta. B cells were identified with CD20, macrophages with CD68, and Class II antigen with anti-HLA DR. Each cell type was semiquantitatively graded in 10 high power fields (HPFs) in the lumenal half (LH) or basal half (BH) of the normal mucosae, and in epithelium or stroma of the carcinomas. In normal colons, ICs were more frequent in LH than in BH. Plasma cells, lymphocytes and monocytes predominated. Subtyping of lymphocytes showed that CD4+ TCR alpha beta + T lymphocytes were most numerous in the lamina propria. Lymphocytes within the epithelium were CD8+ T cells. Around carcinomas the overall grade of ICs was 1+ in the majority of cases. Plasma cells, CD4+ and CD8+ cells with the TCR alpha beta receptor, and macrophages were most frequent. Lymphoid aggregates of both T and B cells were frequent.
CONCLUSIONS: 1. Normal colon contains a diffuse luminally oriented population of TCR alpha beta+ CD4+ T cells, plasma cells, macrophages and class II antigen-expressing cells in the lamina propria.(ABSTRACT TRUNCATED AT 250 WORDS)