Further characterization of lymphocytes from human colonic lamina propria: identification of TG cells.

For the first time, TG cells have been identified in human colon using EDTA-collagenase-prepared, macrophage-depleted isolates of lamina proprial lymphocytes (LPL). Specimens of human colon were obtained from patients undergoing surgery for idiopathic inflammatory bowel disease (IBD), colorectal cancer (Dukes' B or C), other colonic inflammations or benign polyps. Of additional interest were quantitative findings which showed lower TG values in LPL from patients with IBD, regardless of disease activity or steroid therapy, and in Dukes' Group C cancers, compared to the other groups. However, these differences of TG values were not reflected in the peripheral blood lymphocytes (PBL) in which, compared to healthy controls, the numbers of circulating TG cells were greater in patients with Dukes' B or C cancers and in those with moderately or severely active IBD receiving steroids. These quantitative differences re-emphasize the need for concurrent observations on PBL and LPL in these diseases, particularly in experiments to determine the functional properties of their TG subsets, including mediation of natural killing, antibody-dependent cellular cytotoxicity and their immunoregulatory properties. The identification of TG cells per se in colonic LPL provides a basis for such studies.