A Mesenteric Desmoid Tumor with Rapid Progression.

We herein report the case of a rapidly progressive sporadic mesenteric desmoid tumor (DT). A 62-year-old woman presented with a 4-cm-diameter palpable mass in the left supraumbilical area. The mass showed an ill-defined margin with heterogeneous delayed enhancement on computed tomography and heterogeneous high intensity on T2-weighted magnetic resonance imaging. Sixteen months after the initial observation, the mass had grown in size, reaching 13 cm in diameter. The resected mass was histologically confirmed as a DT of the mesentery. Since DT often has an unpredictable clinical course, clinicians should bear in mind the need for imaging follow-up.

Non-paraneoplastic autoimmune subepidermal bullous disease associated with fatal bronchiolitis obliterans.

Bronchiolitis obliterans is a small-airway obstructive lung disease for which immunologically mediated pathogenesis is supposed. Frequent association of bronchiolitis obliterans with paraneoplastic pemphigus is well known, but its association with other autoimmune bullous diseases has not been reported except for a case of anti-laminin-332-type mucous membrane pemphigoid in a patient with chronic graft-versus-host disease. We report a case of non-paraneoplastic autoimmune subepidermal bullous disease associated with fatal bronchiolitis obliterans in a patient without transplantation. Although the patient's serum contained immunoglobulin (Ig)A antibodies to the 180-kDa bullous pemphigoid antigen/type XVII collagen and IgG antibodies to laminin-332, diagnosis of either linear IgA bullous dermatosis or mucous membrane pemphigoid could not be made because of the failure to detect linear IgA deposition at the basement membrane zone by direct immunofluorescence and the lack of mucous membrane lesions. Physicians should be aware that autoimmune bullous diseases other than paraneoplastic pemphigus can also associate with this rare but potentially fatal lung disease.

Primary malignant mesothelioma of the appendix.

We report a case of primary malignant mesothelioma of the appendix. A 35-year-old man without any history of asbestos exposure was admitted to our hospital for further examination following the discovery of multiple liver tumors, an ileocecal tumor, and abdominal lymph node swelling. An ultrasound-guided liver tumor biopsy revealed malignant mesothelioma. Despite receiving systemic chemotherapy, he died 3 months after the initial diagnosis. At autopsy, a diagnosis of multiple organ metastases from a malignant biphasic mesothelioma of the appendix was made. To our knowledge, this is only the second reported case of primary malignant mesothelioma of the appendix.

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.

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.

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) beta+ CD3int cells (50% of them expressed NK1.1) in the liver, whereas it was CD3+ IL-2Rbeta- 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 Jalpha281-/- 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.

Characterization of extrathymic CD8 alpha beta 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, CD8 alpha beta+ 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.

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

Mice were orally administered with beta-glucan, isolated from baker's 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.

Identification of effector cells for TNFalpha-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.