sq-23377 and Colitis--Ulcerative

Abrogating tolerance against unidentified antigens is a critical step in the pathogenesis of ulcerative colitis (UC). T cell anergy, one of the main mechanisms of tolerance, has been shown to be induced by E3 ubiquitin ligases, such as gene related to anergy in lymphocytes (GRAIL), Itch, and c-Cbl in mice. However, it is not well known whether these E3 ligases play roles in human diseases. The pathophysiological role of the E3 ligases in patients with UC was investigated. At first, the expression of GRAIL, Itch, and c-Cbl in human anergic T cells was analyzed by quantitative RT-PCR and Western immunoblotting. Next, the mRNA expression of the E3 ligases was analyzed in peripheral CD4+ T cells of 20 patients with UC and 10 healthy volunteers (HV). mRNA expression was analyzed in patients with active UC before and after treatment with prednisolone and leukocytapheresis. Anergic human CD4+ T cells expressed significantly higher levels of GRAIL, Itch, and c-Cbl than nonanergic cells. GRAIL expression was significantly higher in patients with UC in remission than in patients with active disease and in HV (P < 0.01). The level of GRAIL expression was also significantly increased in patients with active disease whose clinical activity index scores improved after treatment (P < 0.05). There were no significant differences in Itch and c-Cbl expression among patients with active UC, patients with UC in remission, and HV. These data suggest that GRAIL plays an important role in maintaining remission in patients with UC.

Topics: Adolescent; Adult; Aged; CD4-Positive T-Lymphocytes; Cells, Cultured; Colitis, Ulcerative; Female; Humans; Ionomycin; Ionophores; Leukapheresis; Male; Middle Aged; Proto-Oncogene Proteins c-cbl; Repressor Proteins; RNA, Messenger; Ubiquitin-Protein Ligases; Up-Regulation

To investigate the role of local colonic mucosal NK receptor-positive T (NKR(+) T) cells in the regulation of intestinal inflammation, we analyzed the population and function of these cells in ulcerative colitis (UC).. Colonic mucosal tissues were obtained from colonoscopic biopsies of the descending colon from 96 patients with UC (51 endoscopically uninflamed, 45 inflamed) and 18 normal controls. Endoscopic appearance and histologic score at the biopsied site were determined by Matts' classification. A single cell suspension was prepared from each biopsy by collagenase digestion. Two NKR(+) T cell subsets, CD56(+) (CD56(+)CD3(+)) T cells and CD161(+) (CD161(+)CD3(+)) T cells, were detected by flow cytometric analysis. Intracellular cytokine analysis for anti-inflammatory cytokine interleukin-10 (IL-10) was performed by in vitro stimulation with phorbol-myristate-acetate (PMA) and ionomycin.. CD56(+) T cells and CD161(+) T cells are present in the normal human colon and account for 6.7% and 21.3% of all mononuclear cells, respectively. The populations of both CD56(+) T cells and CD161(+) T cells were decreased significantly in the inflamed mucosa of UC. In contrast, the frequency of conventional T cells (CD56(-)CD3(+) cells and CD161(-)CD3(+) cells) was similar among the patient and control groups. The populations of NKR(+) T cells were correlated inversely with the severity of inflammation, which was classified according to the endoscopic and histologic Matts' criteria. Interestingly, approximately 4% of mucosal NKR(+) T cells expressing IL-10 were detected by in vitro stimulation with PMA and ionomycin.. Selective reduction in the population of colonic mucosal NKR(+) T cells may contribute to the development of intestinal inflammation in UC.

Topics: Adult; Aged; Anti-Inflammatory Agents; Antigens, Surface; Azathioprine; CD56 Antigen; Colitis, Ulcerative; Female; Humans; Immunosuppressive Agents; Interleukin-10; Intestinal Mucosa; Ionomycin; Ionophores; Lectins, C-Type; Male; Middle Aged; NK Cell Lectin-Like Receptor Subfamily B; Prednisolone; T-Lymphocyte Subsets; Tetradecanoylphorbol Acetate

Phytohemagglutin in (PHA)-induced IL-2 production in vitro by peripheral blood mononuclear cells (PBMC) and lamina propria mononuclear cells (LPMC) from patients with active UC (n = 24, n = 8, respectively) was significantly less than that in controls (n = 13, n = 8, respectively) and inactive patients (n = 11). In contrast, PBMC from inactive disease showed no significant difference when compared with the controls. Depressed IL-2 production in active UC was not reversed by the addition of anti-CD3 monoclonal antibody plus phorbol myristate acetate (PMA), but was largely reversed by adding calcium ionophore plus PMA. Using a fluorescent Ca2+ probe fura-2, we found that after PHA stimulation LPMC from patients with active UC showed a lower magnitude of rise in intracellular free calcium concentration ([Ca2+]i) than control cells. These results suggest that impaired PHA-induced IL-2 production in active UC may be related to some alterations of the early signaling events that cause elevation of the [Ca2+]i.

Topics: Adult; Aged; Calcium; Cells, Cultured; Colitis, Ulcerative; Female; Humans; Interleukin-2; Intracellular Fluid; Ionomycin; Leukocytes, Mononuclear; Male; Middle Aged; Muromonab-CD3; Phytohemagglutinins; Tetradecanoylphorbol Acetate

There is increasing evidence that ulcerative colitis is associated with an abnormality of the immune system. Although the aetiology remains unknown, it has been suggested that the immune system of these patients is implicated in the pathogenesis of their disease. T cell function was investigated in ulcerative colitis patients and defective phytohaemagglutinin induced T cell mitogenesis was found. The DNA synthesis induced by stimulation with phorbol esters plus ionophore (ionomycin), however, was normal. These changes cannot be ascribed to either decreased interleukin 2 synthesis or to a defective interleukin 2 receptor expression after cellular activation. Moreover, this defective proliferative response of the T lymphocytes was observed even in the presence of saturated concentrations of exogenous interleukin 2. These results emphasise that the interleukin 2 dependent proliferation pathway is deficient in T lymphocytes from ulcerative colitis patients.

Topics: Adolescent; Adult; Aged; Cell Division; Cell Membrane; Cells, Cultured; Colitis, Ulcerative; DNA; Female; Humans; Interleukin-2; Ionomycin; Male; Middle Aged; Phytohemagglutinins; Receptors, Interleukin-2; Stimulation, Chemical; T-Lymphocytes; Tetradecanoylphorbol Acetate