Yuiko Ishimoto

Immunopotentiation of intraepithelial lymphocytes in the intestine by oral administrations of β-glucan

Mice were orally administered with beta-glucan, isolated from bakers yeast, daily for one week (25mg/day/mouse) and several immunoparameters in the digestive tract were examined. The most prominent change was an increase in the number of intraepithelial lymphocytes (IEL) in the intestine, although the number of lymphocytes in the liver remained unchanged. The absolute number of both alphabetaT cells and gammadeltaT cells expressing CD8 antigens increased among IEL in the intestine. Primarily, liver lymphocytes showed a spontaneous production of Type 0 cytokine (simultaneous production of IFNgamma and IL-4) while IEL did not produce any cytokines without stimulation. However, mice administered with beta-glucan produced Type 1 cytokine, namely, production of IFNgamma alone. These results suggest that beta-glucan may be an important potentiator for mucosal immunity in the digestive tract.

Improved survival with oral administration of enteric‐coated tegafur/uracil for advanced stage IV‐A hepatocellular carcinoma

Background and Aims: There is currently no proven chemotherapy regimen for hepatocellular carcinoma (HCC). The principal chemotherapeutic approach in most cases is infusion therapy into the hepatic arteries feeding the tumors. However, the clinical effects of chemotherapy are extremely poor. Therefore, in the present study, we conducted a prospective randomized trial of the efficacy of oral administration of enteric‐coated tegafur/uracil for advanced HCC.

Age-dependent variation in the proportion and number of intestinal lymphocyte subsets, especially natural killer T cells, double-positive CD4+ CD8+cells and B220+ T cells, in mice

The age‐dependent variation in the proportion and number of lymphocyte subsets was examined at various extrathymic sites, including the liver, small intestine, colon and appendix in mice. In comparison with young mice (4 weeks of age), the number of total lymphocytes yielded by all tested organs was greater in adult (9 weeks) and old (40 weeks) mice. The major lymphocyte subset that expanded with age was interleukin‐2 receptor (IL‐2R) β+ CD3int cells (50% of them expressed NK1.1) in the liver, whereas it was CD3+ IL‐2Rβ– NK1.1– cells at all intraepithelial sites in the intestine. Although NK1.1+ CD3+ cells were present at intraepithelial sites in the intestine, the proportion of this subset was rather low. The ratio of CD4 to CD8 tended to decrease among natural killer T (NKT) cells and T cells at all intraepithelial sites in the intestine with age. A unique population of double‐positive CD4+ CD8+ cells in the small intestine increased in old mice. B220+ T cells were found mainly in the appendix and colon, and the proportion of these T cells decreased in old mice. Conventional NKT cells were very few in Jα281–/– and CD1d–/– mice in the liver, while NKT cells which existed in the appendix remained unchanged even in these mice. This was because unconventional CD8+ NKT cells were present in the intestine. The present results suggest that despite the fact that both the liver and intraepithelial sites in the intestine carry many extrathymic T cells, the distribution of lymphocyte subsets and their age‐associated variation are site‐specific.

Complete remission of multiple hepatocellular carcinomas associated with hepatitis C virus-related, decompensated liver cirrhosis by oral administration of enteric-coated tegafur/uracil

We report a case of complete remission of multiple hepatocellular carcinomas after oral administration of enteric-coated tegafur/uracil. A 77-yr-old woman was diagnosed as having recurrent hepatocellular carcinoma associated with decompensated liver cirrhosis. We administered enteric-coated tegafur/uracil to this patient. After 1 month of oral administration, there was a decrease in tumor markers. An image analysis showed disappearance of hepatocellular carcinoma. No recurrence of the hepatocellular carcinoma was recognized for 18 months up to the time of the patients death, which was due to massive bleeding from a hemorragic rectal ulcer. At autopsy, the tumor lesion had necrotized. Oral administration of enteric-coated granules containing tegafur/uracil may provide an effective treatment for hepatocellular carcinoma.

Identification of effector cells for TNFα-mediated cytotoxicity against WEHI164S cells

WEHI164S cells were found to be very sensitive targets for in vitro killing in a 6-h culture when liver or splenic lymphocytes were used as effector cells in mice. Of particular interest, a limiting cell-dilution analysis showed that effector cells were present in the liver with a high frequency (1/4,300). In contrast to YAC-1 cells as NK targets, perforin-based cytotoxicity was not highly associated with WEHI164S killing. The major killer mechanism for WEHI164S targets was TNFalpha-mediated cytotoxicity. By cell sorting experiments, both NK cells and intermediate T cells (i.e., TCR(int) cells) were found to contain effector cells against WEHI164S cells. However, the killer mechanisms underlying these effector cells were different. Namely, NK cells killed WEHI164S cells by perforin-based cytotoxicity, TNFalpha-mediated cytotoxicity, Fas ligand cytotoxicity, and other mechanisms, whereas intermediate T cells did so mainly by TNFalpha-mediated cytotoxicity. These results suggest that TNFalpha-mediated cytotoxicity mediated by so-called natural cytotoxic (NC) cells comprised events which were performed by both NK and intermediate T cells using somewhat different killer mechanisms. Intermediate T cells which were present in the liver were able to produce TNFalpha if there was appropriate stimulation.

Hepatic natural killer and natural killer T cells markedly decreased in two cases of drug‐induced fulminant hepatic failure rescued by living donor liver transplantation

Abstract  The human liver contains significant numbers of innate immune cells, such as natural killer (NK) cells and natural killer T (NKT) cells, which express both T‐cell receptors and NK‐cell receptors simultaneously. It has been suggested that the innate immune system plays a crucial role in the liver. In this report, the distribution of NK and NKT cells in the liver and peripheral blood of two patients with drug‐induced fulminant hepatic failure (FHF) who had undergone living donor liver transplantation was examined. In both the liver and peripheral blood, the proportions of NK and NKT cells markedly decreased compared with those in healthy donors. It was also revealed that, unlike murine NKT cells, human CD56+ T cells and CD57+ T cells did not constitutively express CD28, which is one of the important costimulatory molecules on T cells. Additionally, the residual CD56+ T cells and CD57+ T cells in the patients expressed more CD28 than in controls. This result suggests that NKT cells might be more activated in FHF. Although the accumulation of further cases is required, it is suggested that both NK and NKT cells might be involved in hepatic injury in FHF.

Characterization of extrathymic CD8αβ T cells in the liver and intestine in TAP-1 deficient mice

TAP‐1 deficient (−/−) mice cannot transport MHC class I antigens onto the cell surface, which results in failure of the generation of CD8+ T cells in the thymus. In a series of recent studies, it has been proposed that extrathymic T cells are generated in the liver and at other extrathymic sites (e.g. the intestine). It was therefore investigated whether CD8+ extrathymic T cells require an interaction with MHC class I antigens for their differentiation in TAP‐1(−/−) mice. Although CD8+ thymically derived T cells were confirmed to be absent in the spleen as well as in the thymus, CD8αβ+ T cells were abundant in the livers and intestines of TAP‐1(−/−) mice. These CD8+ T cells expanded in the liver as a function of age and were mainly confined to a NK1·1−CD3int population which is known to be truly of extrathymic origin. Hepatic lymphocytes, which contained CD8+ T cells and which were isolated from TAP‐1(−/−) mice (H‐2b), responded to neither mutated MHC class I antigens (bm1) nor allogeneic MHC class I antigens (H‐2d) in in vitro mixed lymphocyte cultures. However, the results from repeated in vivo stimulations with alloantigens (H‐2d) were interesting. Allogeneic cytotoxicity was induced in liver lymphocytes in TAP‐1(−/−) mice, although the magnitude of cytotoxicity was lower than that of liver lymphocytes in immunized B6 mice. All allogeneic cytotoxicity disappeared with the elimination of CD8+ cells in TAP‐1(−/−) mice. These results suggest that the generation and function of CD8+ extrathymic T cells are independent of the existence of the MHC class I antigens of the mouse but have a limited allorecognition ability.

Protection against malaria by anti-erythropoietin antibody due to suppression of erythropoiesis in the liver and at other sites

We have previously reported that erythropoiesis commences in the liver and spleen after malarial infection, and that newly generated erythrocytes in the liver are essential for infection of malarial parasites as well as continuation of infection. At this time, erythropoietin (EPO) is elevated in the serum. In the present study, we administered EPO or anti‐EPO antibody into C57BL/6 (B6) mice to modulate the serum level of EPO. When mice were infected with a non‐lethal strain (17NXL) of Plasmodium yoelii (blood‐stage infection of 104 parasitized erythrocytes per mouse), parasitemia continued for 1 month, showing a peak at day 17. Daily injection of EPO (200 IU/day per mouse) from day five to day 14 prolonged parasitemia, whereas injection of anti‐EPO antibody (1.5 mg/day per mouse) every second day from day five to day 28 decreased it. Erythropoiesis was confirmed in the liver, spleen and bone marrow by the appearance of nucleated erythrocytes (TER119+). When anti‐EPO antibody was injected by the same protocol into mice infected with a lethal strain (17XL) of P. yoelii, all mice showed decreased parasitemia and recovered from the infection. These results suggest that the use of anti‐EPO antibody after malarial infection may be of therapeutic value in severe cases of malaria.

7070 Endoscopic follow-up study of ulcerative colitis with skipped appendiceal involvement.

Background and aims : Recently it has been reported that appendiceal involvement can occur as a skip lesion in ulcerative colitis (UC), although the clinical significance of this finding is still debatable. In such cases, we evaluated the changes in disease extent endoscopically and histologically, and also assessed the presence of appendiceal orifice (AO) inflammation. Materials and methods : From January 1993 to August 1999, a total of 17 patients with skipped AO involvement were entered into this study with their informed consent. All of them received medical therapy, and colonoscopy was performed twice or more at intervals of more than 3 months. Results : The patients with endoscopically skipped AO involvement were divided into two groups with respect to disease extent; 6 (3M, 3F; median age at disease onset 36 yr; range 20-65 yr) showed fixed areas that were spared endoscopically and histologically (S-type), and 11 (8M, 3F; 23 yr; range 13-46 yr) showed endoscopically active lesions in some areas at some time, histological examination revealing continuous pancolitis (C- type). The median follow-up periods were 23.7 (range 12-39) months for the Stype and 29 (3-47) months for the C-type. The median times of colonoscopic examinations were 4 (2-6) and 4 (2-8) months,respectively. The transverse colon was affected significantly less frequently in the S-type than in the C-type (p=0.03). There was a close correlation (p=0.005) between the activity of AO and that of the main lesion in the S-type, but not in the Ctype. Conclusion :Cases of UC with endoscopically skipped AO lesions were divided into two types; those showing histological skipping and those showing histological continuity. In the S-type, AO inflammation was correlated with the activity of the main lesions, and active lesions were rarely found in the transeverse colon. In the C-type, although histological continuity was evident, relapse as pancolitis seldom or never occurred.