The mononuclear cells of human mesenteric blood, intestinal mucosa and mesenteric lymph nodes: compartmentalization of NK cells.

The proportions of T cell subsets and Leu 7+ cells and the spontaneous cell-mediated cytotoxicity (SCMC) of isolated mononuclear cells have been determined across the mesenteric vascular bed and along the intestinal mucosal-mesenteric lymph node (MLN) axis in patients undergoing abdominal surgery. Whereas the proportion of T4+ and T8+ cells were similar in simultaneously taken PVB and mesenteric venous blood (MVB), the proportion of Leu 7+ cells was higher in MVB in 16 of 17 studies (15.4 +/- 6.8%, 10.8 +/- 5.1%). Additional studies showed that the proportions of lymphocyte subsets in peripheral arterial blood are the same as those in PVB. Thus, an enrichment of Leu 7+ cells occurs across the mesenteric vascular bed. Isolated intestinal and MLN mononuclear cells contained similarly high proportions of T4+ and T8+ cells as in PVB but Leu 7+ cells made up a minority subpopulation in intestinal (1.3 +/- 0.8%) and MLN mononuclear cells (1.0 +/- 0.9%). The SCMC of intestinal and MLN mononuclear cells was low and paralleled the proportion of Leu 7+ cells. Despite the higher proportions of Leu 7+ cells in MVB, the SCMC was less than that of PVB in eight patients with inflamed intestine and not significantly different from PVB in seven patients with normal intestines. These paradoxical findings were at least in part due to inhibitory factors in mesenteric plasma. In conclusion, NK cells appear to be largely confined within the vascular system and the enrichment of Leu 7+ cells across the mesenteric vascular bed suggests that this compartmentalization may be due to differences in the traffic of lymphocyte subpopulations through the intestinal mucosa and MLN.