Circulating CD4+CD25+ Regulatory T Cells in the Pathobiology of Ulcerative Colitis and Concurrent Primary Sclerosing Cholangitis

Background

Immunopathogenetic features of primary sclerosing cholangitis (PSC) in ulcerative colitis (UC) still remains unclear. Peripheral blood CD4+CD25+ regulatory T cells have a key role in the induction and maintenance of peripheral self-tolerance and inhibit several organ-specific autoimmune diseases. Therefore, CD4+CD25+ T cells are believed to play an essential role in autoimmune diseases. The aim of the present study is to analyze the role of CD4+CD25+ T cells in the pathogenesis of UC-associated PSC.

Methods

This study evaluated the levels of CD4+CD25+ T cells in peripheral blood mononuclear cells (PBMC) of 27 UC patients with PSC and 20 UC patients as controls. CD4+CD25+ T cells were isolated from PBMC with a direct immunofluorescence technique, using mice monoclonal antibodies namely FITC-labeled anti-CD4 and PE-labeled anti-CD25. In each patient, CD4+CD25+ T cells percentage in PBMC were studied by flow cytometry, and then the number of CD4+CD25+ T cells were calculated.

Results

Twenty-seven UC patients with PSC and 20 UC patients without PSC as controls were enrolled in the present study. The percentage of CD4+CD25+ regulatory T cells among PBMC were significantly elevated in UC + PSC patients compared with UC patients without PSC (p = 0.04).

Conclusions

CD4+CD25+ T cells were found to be elevated in UC patients with PSC suggesting a partial role of activated T cell response in the disease pathophysiology. Our findings imply that CD4+CD25+ regulatory T cells may play a key role in the immunopathogenesis of UC-associated PSC and may affect the therapeutic management of these diseases.     

γ-干扰素和CD40配体刺激下大鼠血管平滑肌细胞凋亡与钙调神经磷酸酶的相关性

目的 观察在炎症因子γ-干扰素和CD40配体刺激下大鼠血管平滑肌细胞的凋亡及钙调神经磷酸酶活性和表达水平的变化,进一步探讨血管平滑肌细胞凋亡的机制.方法 取200～250 g雄性清洁级SD大鼠,分离胸主动脉进行血管平滑肌细胞培养并分别给予炎症因子γ-干扰素、CD40配体和γ-干扰素+CD40配体共刺激及加入钙调神经磷酸酶阻断荆FK506处理.采用Western Blot检测钙调神经磷酸酶表达水平;定磷法检测钙调神经磷酸酶活性,流式细胞仪检测细胞表面CD40表达及平滑肌细胞凋亡.结果 对照组可表达一定量的CD40,用γ-干扰素刺激细胞后,细胞表面CD40荧光阳性细胞比率增高(18.5%±0.2%比44.2%±2.4%).用γ-干扰素、CD40配体分别刺激血管平滑肌细胞,钙调神经磷酸酶活性[分别为6.48±1.09 mmolPi/(g.h)和6.26±1.47 mmolPi/(g.h)]及表达水平(分别为0.82±0.24和0.73±0.20)均显著高于对照组[分别为1.56±0.53 mmolPi/(g.h)和0.38±0.12,P<0.01],γ-干扰素与CD40配体共刺激下钙调神经磷酸酶活性[11.70±2.73 mmolPi/(g.h)]及表达水平(2.85±0.61)较其余各组显著增高(P<0.01),平滑肌细胞凋亡水平显著高于其他刺激组.FK506作用下钙调神经磷酸酶活性[2.74±0.30 mmolPi/(g.h)]降低,平滑肌细胞凋亡水平较刺激组显著减少(P<0.01).钙调神经磷酸酶活性与凋亡水平呈显著正相关(P<0.05).结论 炎症因子γ-干扰素可促进血管平滑肌细胞表面CD40表达增加,通过CD40-CD40配体信号通路活化钙调神经磷酸酶,使血管平滑肌细胞的凋亡增加.     

Lack of Concomitant Expression of ICAM-1 and HLA-DR on Bile Duct Cells from Patients with Primary Sclerosing Cholangitis and Primary Biliary Cirrhosis

In both primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) prominent infiltrates of lymphocytes surround the bile ducts, on which an abberrant expression of major histocompatibility complex class II antigens has been found, suggesting that the immune system is involved in the biliary destruction. Since the lymphocytes presumably must adhere to the bile ducts to initiate a cell-to-cell-mediated destruction, we have studied the expression of the lymphocyte function-associated antigen-1 (LFA-1) together with its ligand, the intercellular adhesion molecule-1 (ICAM-1), and the expression of HLA-DR, using immunoperoxidase staining of cryostat sections from patients with PBC (n = 10), PSC (n = 13), and normal healthy controls (n = 6). Most lymphocytes expressed LFA-1. ICAM-1 expression was found on hepatocytes from 9 of 10 PBC and 10 of 13 PSC patients but was not seen on hepatocytes from the controls. Hepatocytes expressing HLA-DR were only found in one patient with PBC. None of the septal bile ducts expressed ICAM-1, and only one PSC patient and three PBC patients expressed ICAM-1 on their interlobular bile ducts. The bile ducts in 22 of 23 patients, however, expressed HLA-DR. Proliferating bile ductules from two PBC patients and three PSC patients showed a concomitant expression of ICAM-1 and HLA-DR. None of the bile ducts from the controls expressed ICAM-1 or HLA-DR. Thus, since most bile ducts involved in the disease process of both PBC and PSC lack expression of ICAM-1, other adhesion molecules must be involved if a cell-to-cell-mediated destruction accounts for the biliary destruction in these two disease states. Furthermore, the lack of concomitant expression of HLA-DR and ICAM-1 on the bile ducts in PBC and PSC indicates that other regulatory mechanisms exist in the biliary epithelium than in most other epithelial cells.     

The Effect of Beta Interferon on Dendritic Cells and Cytokine Synthesis by CD4+ T Cells

Background: Dendritic cells (DC) are a key regulator of the immune response, and interferon- beta (IFN-β) is considered an immunomodulatory molecule for DC. Objective: The purpose of this study was to evaluate the ability of IFN-β treated DC to induce cytokine secretion by CD4+ T cells. Methods: Dendritic cells were generated from blood monocytes with granulocyte-monocyte colony-stimulating factor and interleukin-4 with or without IFN-β. We analyzed the production of CD4+ T helper cytokines (IL-17, IFN- γ and IL-10) in the supernatant of the dendritic cell-T cell co- cultures by ELISA. We also studied the effects of HLA-G and costimulatory molecules on immature and mature DC. Results: IFN-γ and IL-17 decreased significantly in the presence of HLA-Gbearing DC compared to control cultures (p<0.05). Conclusion: Using the mixed leukocyte reaction, we found that DC treated with IFN-β mediated the inhibition of T cell activation via cytokine production. We conclude that this is important for preventing overactivation of the immune system.     

Prognostic Impact of Circulating CD28 Negative Suppressor T Cells and Memory B Cells on Treatment Outcomes of Patients with Breast Cancer

Background: It has been suggested that routine assessment and quantification of different lymphocyte subsets can provide clinically meaningful prognostic information in breast cancer (BC). Objective: To determine the relationship between peripheral blood lymphocyte subsets and pathological parameters and response to therapy in patients with BC. Methods: Thirty patients with operable breast cancer treated surgically with either modified radical mastectomy or breast conservative surgery, and 20 healthy controls were included. For detection of lymphocyte subsets in peripheral blood; Fluorochrome-labeled monoclonal antibodies were used and cells were analyzed by flow cytometry. Patients were treated with chemotherapy, radiotherapy and hormonal treatment, and followed up to determine relapse and recurrence-free survival (RFS). Results: Significant differences were found in the frequencies of B, T, NK, NKT, and CD28‒T cells between patients with BC and controls. Moreover, a significant difference was found in the percentage of CD8+CD28‒ T cells between patients with different pathologic subtypes of BC and negative correlations were observed between the frequency of CD8+CD28‒T cells and memory B cells, and RFS. Also, a significant difference in the frequency of naïve B cells was found in patients with different tumor grades and a negative correlation was found between the frequencies of B cells and NKT cells. Conclusion: NK, NKT, lymphocytes, and CD28‒ T cells significantly differed between healthy controls and BC patients. Also, memory B cells were associated with good response to treatment while CD28‒ T cells were associated with shorter RFS.