Ulcerative colitis, autoimmune epiphenomena, and colonic cancer

Ulcerative colitis specific cytotoxic IgG-autoantibodies against colonic epithelial cancer cells

Serum antibodies cytotoxic to the colon cancer cell line RPMI 4788 were studied in 42 patients with ulcerative colitis, 61 patients with Crohn's disease, 27 patients with other inflammatory diseases (disease-controls) and 22 healthy controls. Cytotoxicity of antibodies towards RPMI 4788 was studied by means of a chromium release assay using peripheral blood mononuclear leucocytes of healthy subjects as effector cells. Using a four hour antibody dependent cell mediated cytotoxicity assay sera from 29% of ulcerative colitis patients contained antibodies cytotoxic for the target, while only 3% of the Crohn's patients and 6% of the disease controls and non of the healthy controls were positive. When an 18 hour assay was applied, however, not only 40% of ulcerative colitis patients, but also 14% of Crohn's patients and 21% of disease controls were found positive. The reactive antibody in the four hour assay was mainly of the IgG class, which points at a classical antibody dependent cell mediated cytotoxicity mechanism. In the 18 hour cytotoxic assay IgG and particularly IgM antibodies were found to be reactive. This suggests that in the latter case other cellular cytotoxic mechanism might be involved. There was a significant inverse correlation between the appearance of the ulcerative colitis restricted IgG-anticolon epithelial cell antibodies (four hour assay) and the disease activity (p less than 0.01). Absorption studies showed that the reactive antigen is not specific for ulcerative colitis colonic tissue, but is similarly found in Crohn's bowel tissue, and to a lower extent in normal bowel, liver and kidney. The reactive antigen, however, could not be detected in brain and lymphoblastoid cells.

Increased incidence of urethane induced lung adenomata by autosensitized lymphocytes

The present work investigates the influence of autosensitized lymphocytes on the carcinogenic response of the host. Urethane treated SWR mice received 6 fortnightly injections of lymphocytes sensitized in vitro against syngeneic fibroblasts. An increased incidence of lung adenomata was found in these mice compared with controls injected with unsensitized lymphoid cells or with lymphoid cells sensitized against unrelated transplantation antigens. Autosensitized lymphocytes also modified the response of host lymphoid cells to concanavalin A or to stimulation in a mixed lymphocyte culture assay. These results indicate that autoimmune lymphocytes may increase susceptibility of a host to the induction of tumours.

Lymphoblastic response to autologous colon epithelial cells in ulcerative colitis in vitro

The blastic transformation in vitro of peripheral blood lymphocytes was measured by the 72-hour uptake of tritiated thymidine ((3)H-6-thymidine) in 23 patients with mucosal ulcerative colitis, three patients with acute Crohn's colitis with rectal involvement, and seven normal subjects. The 23 patients with ulcerative colitis were subdivided into three groups, graded according to severity into seven with acute, severe, nine with active, chronic, and seven with quiescent disease. In the control cultures of lymphocytes without any added potential stimulant the uptake of (3)H-6-thymidine in the clinical subgroup of seven patients with acute, severe ulcerative colitis was significantly greater than in seven normal subjects (p<0.01). This contrasted with a reduced uptake of (3)H-6-thymidine by lymphocytes from seven patients with acute severe colitis when compared with seven normal subjects after stimulation with phytohaemagglutinin-P (PHA-P) (p<0.01). In further duplicate cultures of lymphocytes specifically stimulated by an equal number of viable autologous rectal epithelial cells, the uptake of (3)H-6-thymidine was significantly greater in seven patients with acute severe colitis when compared with seven normal subjects (p<0.01). The results in three patients with acute Crohn's colitis with rectal involvement showed no such evidence of lymphocyte sensitivity to autologous rectal epithelial cells and their uptake of (3)H-6-thymidine lay within the normal range.Evidence that the degree of lymphoblastic transformation was related to the clinical severity of ulcerative colitis was provided by the results obtained in the unstimulated and epithelial cell stimulant cultures. The uptake of (3)H-6-thymidine was directly related to the clinical severity of ulcerative colitis in the three subgroups studied. In addition, four of the seven patients with acute severe colitis were studied later in clinical remission. They were then found to have a significantly reduced uptake of (3)H-6-thymidine in response to autologous rectal epithelial cells (p < 0.01).

Studies of carcinoembryonic antigen activity of whole and extracted serum in ulcerative colitis

The present study has used a microradioimmunoassay to detect carcinoembryonic antigen(s) (CEA) in whole and extracted serum in 77 patients with ulcerative colitis, two of whom had coexisting colonic carcinoma, and 69 patients with carcinoma of the colon or rectum. Taking 5 ng/ml as the level of positivity, the CEA assay on whole serum showed positive results in patients with ;active' ulcerative colitis (15 of 17) but not in those with ;inactive' disease (0 of 23). In two patients, levels fell during drug-induced remission. Our results also indicated that a positive result for CEA on extracted serum was associated with carcinomatous changes in ulcerative colitis in contrast to uncomplicated ulcerative colitis in which positive results were obtained only with whole serum.