Chun-Yen Lin

Dominant transplantation tolerance impairs CD8 + T cell function but not expansion

Alloreactive CD8+ T cells may persist in animals made tolerant of transplanted tissues; their function is controlled through continuous censorship by regulatory CD4+ T cells. We sought to establish the stage at which such censorship operates. We found that monospecific CD8+ T cells introduced into tolerant animals responded to the tolerated tissue antigen as if they had received CD4+ T cell “help”: they proliferated and accumulated normally. However, they did show compromised graft rejection, interferon-γ production and cell-mediated cytotoxicity. These findings suggest that tolerance mediated by regulatory T cells acts by censoring immune effector functions rather than by limiting the induction of T cell responses.

IL28B SNP rs12979860 is a critical predictor for on-treatment and sustained virologic response in patients with hepatitis C virus genotype-1 infection.

Background Single nucleotide polymorphisms (SNPs) of interleukin-28B (IL28B) have received considerable interest for their association with sustained virological response (SVR) when treating patients of genotype-1 hepatitis C virus (GT1-HCV) chronic infection with pegylated interferon and ribavirin (PegIFN/RBV). This study was to investigate the predictive power of IL28B SNPs for on-treatment responses and SVR in treatment-naïve patients with GT1-HCV chronic infection. Methodology/Principal Findings We analyzed ten SNPs of IL28B in 191 treatment-naïve patients with GT1-HCV chronic infection who received PegIFN/RBV. In these patients, rapid virological response (RVR), early virological response (EVR) and SVR were achieved in 69.6%, 95.8% and 68.6% of the patients, respectively. Multivariate analysis (odds ratio; 95% confidence interval; P value) indicated age (0.96; 0.93–0.99; 0.012), low baseline viral load (4.65; 2.23–9.66; <0.001) and CC genotype of rs12979860 (7.74; 2.55–23.53; <0.001) but no other SNPs were independent predictors for SVR. In addition, none of the ten SNPs examined were associated with baseline viral load and stages of liver fibrosis. Regarding RVR, low baseline viral load (2.83; 1.40–5.73; 0.004) and CC genotype of rs12979860 (10.52; 3.45–32.04; <0.001) were two critical predictors. As for EVR, only CC genotype of rs12979860 (36.21; 6.68–196.38; <0.001) was the predictor. Similarly, for end of treatment response (ETR), CC genotype of rs12979860 (15.42; 4.62–51.18; <0.001) was the only predictor. For patients with RVR, only low baseline viral load (3.90; 1.57–9.68; 0.003) could predict the SVR. For patients without RVR, only rs12979860 (4.60; 1.13–18.65; 0.033) was the predictor for SVR. Conclusions/Significance rs12979860 is the critical predictor for RVR, EVR, ETR and SVR in treatment-naïve patients of GT1-HCV chronic infection. Furthermore, this SNP is the only predictor for SVR in patients without RVR. These results have provided evidence that rs12979860 is the ideal IL28B SNP for genetic testing in treating patients of GT1-HCV chronic infection.

Tumor-Derived Chemokine CCL5 Enhances TGF-β–Mediated Killing of CD8+ T Cells in Colon Cancer by T-Regulatory Cells

Chemokine CCL5/RANTES is highly expressed in cancer where it contributes to inflammation and malignant progression. In this study, we show that CCL5 plays a critical role in immune escape in colorectal cancer. We found that higher levels of CCL5 expression in human and murine colon tumor cells correlated with higher levels of apoptosis of CD8+ T cells and infiltration of T-regulatory cells (T(reg)). In mouse cells, RNA interference (RNAi)-mediated knockdown of CCL5 delayed tumor growth in immunocompetent syngeneic hosts but had no effect on tumor growth in immunodeficient hosts. Reduced tumor growth was correlated with a reduction in T(reg) infiltration and CD8(+) T-cell apoptosis in tumors. Notably, we found that CCL5 enhanced the cytotoxicity of T(reg) against CD8(+) T cells. We also found tumor growth to be diminished in mice lacking CCR5, a CCL5 receptor, where a similar decrease in both T(reg) cell infiltration and CD8(+) T-cell apoptosis was noted. TGF-β signaling blockade diminished apoptosis of CD8(+) T cells, implicating TGF-β as an effector of CCL5 action. In support of this concept, CCL5 failed to enhance the production of TGF-β by CCR5-deficient T(reg) or to enhance their cytotoxic effects against CD8(+) T cells. CCR5 signaling blockade also diminished the in vivo suppressive capacity of T(reg) in inhibiting the antitumor responses of CD8(+) T cells, in the same way as CCL5 signaling blockade. Together, our findings establish that CCL5/CCR5 signaling recruits T(reg) to tumors and enhances their ability to kill antitumor CD8(+) T cells, thereby defining a novel mechanism of immune escape in colorectal cancer.

Helicobacter pylori in cirrhotic patients with peptic ulcer disease: A prospective, case controlled study

BACKGROUND There is an increased prevalence of peptic ulcer disease in patients with liver cirrhosis, but the role of Helicobacter pylori is unclear. METHODS lgG antibodies against H. pylori were measured in 60 patients with compensated liver cirrhosis, in 60 sex- and age-matched patients with compensated liver cirrhosis, and in 60 normal controls. All patients received panendoscopic examinations to search for the evidence of esophageal varices, congestive gastropathy, and peptic ulcers. RESULTS Duodenal ulcers were more common in compensated and decompensated cirrhotic patients (16.7% and 13.3%, respectively) than in normal controls (3.3%, p < 0.05). Gastric ulcers were more frequent in decompensated (15.0%) than compensated cirrhotic patients and normal controls (3.3% and 1.7%, respectively, p < 0.05). The prevalence of H. pylori was not statistically different among the three groups (normal 60.0%, compensated 61.7%, and decompensated, 75.0%; p > 0.05). The prevalence of H. pylori also showed no statistical differences in respect to duodenal ulceration (100%, 80%, and 87.5%, respectively, p > 0.05). The prevalence of H. pylori did not differ significantly in relation to the presence or absence of esophageal varices (68.4% vs 100% if no varices, p = 0.04) and in the presence of congestive gastropathy (50.0 vs 94.7%, p = 0.03). CONCLUSIONS The prevalence of peptic ulcer was increased in cirrhotic patients, but the prevalence of H. pylori was similar in compensated cirrhotic patients, decompensated cirrhotic patients, and normal controls. The frequency of non-H. pylori-associated peptic ulcers in cirrhotic patients was increased in the presence of esophageal varices or congestive gastropathy.

Hepatitis B virus–DNA level and basal core promoter A1762T/G1764A mutation in liver tissue independently predict postoperative survival in hepatocellular carcinoma

Hepatitis B virus (HBV) is a major etiological factor of hepatocellular carcinoma (HCC). However, the postoperative prognostic value of the virological factors assayed directly from liver tissue has never been investigated. To address this issue, 185 liver samples obtained from the noncancerous part of surgically removed HBV‐associated HCC tissues were subjected to virological analysis. Assayed factors included the amount of HBV‐DNA in the liver tissues; genotype; and the presence of the HBV precore stop codon G1896A mutation, basal core promoter A1762T/G1764A mutation, and pre‐S deletions/stop codon mutation. All virological factors and clinicopathological factors were subjected to Cox proportional hazard model analysis to estimate postoperative survival. It was found that an HBV‐DNA level >3.0 × 107 copies/g of liver tissue and the presence of the basal core promoter mutation independently predicted disease‐free (adjusted hazard ratio 1.641 [95% confidence interval (CI) 1.010‐2.667] and 2.075 [95% CI 1.203‐3.579], respectively) and overall (adjusted hazard ratio 2.807 [95% CI 1.000‐7.880] and 5.697 [95% CI 1.678‐19.342], respectively) survival. Kaplan‐Meier survival analysis indicated that in‐frame, short stretch (<100 bp) pre‐S deletions, but not large fragment (>100 bp) pre‐S deletions, were significantly associated with poorer disease‐free (P = 0.005) and overall (P = 0.020) survival. A hot deletion region located between codons 107 and 141 of the pre‐S sequence was identified for the short stretch pre‐S deletion mutants. Conclusion: The amount of HBV‐DNA in liver tissue and the presence of the basal core promoter mutation were two independent predictors for postoperative survival in HCC. A short stretch pre‐S deletion located between codons 107 and 141 was strongly associated with a poorer postoperative prognosis. (Hepatology 2010)

Prevalence of and risk factors for gallbladder polyps detected by ultrasonography among healthy Chinese: Analysis of 34 669 cases

Background and Aim:  Gallbladder (GB) polyps are tumor or tumor‐like projections arising from GB mucosa. Although most polyps are benign, some early GB carcinomas present as polypoid lesions. The diagnosis of GB polyps is relatively easy by ultrasonography. Although numerous studies have investigated GB polyps, few studies have addressed the prevalence of and factors associated with GB polyps for specific ethnic populations. This study analyzes the prevalence and factors associated with GB polyps in a Chinese population who can afford a paid general checkup.

A Strong Association Between Down-Regulation of HLA-DR Expression and the Late Mortality in Patients with Severe Acute Pancreatitis

OBJECTIVES:There is no reliable parameter to predict the late mortality of patients with severe acute pancreatitis though it is an important issue. Recently a proposed parameter for “immunoparalysis,” a down-regulation of Human Leukocytes Antigens-DR (HLA-DR) expression on monocytes, had been detected in patients with severe but not mild acute pancreatitis. However, the relationship between this parameter and late mortality of acute pancreatitis is still unclear. Therefore, we conducted this study in order to elucidate this issue.METHODS:Twenty-five patients of severe acute pancreatitis admitted to Chang-Gung Memorial Hospital were successively enrolled during the period of 1999–2002. The HLA-DR expression, and serum levels of interleukin-10 (IL-10) and tumor necrosis factor-α(TNF-α) at different time points were measured. The HLA-DR expression was evaluated by flow cytometry and the levels of IL-10 and TNF-α were measured by ELISA.RESULTS:In our series, there were 7 (28%) late mortality cases out of 25 patients with severe acute pancreatitis. When analyzing the serial change of HLA-DR expression, it is clear that in survival group the HLA-DR expression was gradually up-regulated and in late mortality group it was persistently down-regulated (p < 0.001). When comparing with other parameters like Acute Physiological and Chronic Health Evaluation II and Ransons score by Cox hazards model, the HLA-DR expression on 10th day (HLA-DR-10) gave the only statistically significant correlation with late mortality (p= 0.001). Furthermore, HLA-DR10 is also a good predictor for late mortality when analyzed by receiver-operating characteristics (ROC) curves with 0.944 area under ROC (AUROC) value. The optimal cutoff value of HLA-DR on 10th day for predicting late mortality was 52.3% with 94.4% sensitivity and 85.7% specificity. As for the serum levels of TNF-α and IL-10, there were significant persistently higher levels in late mortality group than in survival group (p < 0.05). Furthermore, these monocytes from severe acute pancreatitis were with partial restoration of HLA-DR expression but with normal TNF-α and IL-10 secretion ability when stimulated in vitro with LPS.CONCLUSIONS:In severe acute pancreatitis, there was a strong association between the persistent down-regulation of HLA-DR expression and the late mortality. Furthermore, a cutoff value of 52.3% of HLA-DR expressed monocytes on the 10th hospitalization day is a good predictor for late mortality in patients with severe acute pancreatitis.

Activated but not resting regulatory T cells accumulated in tumor microenvironment and correlated with tumor progression in patients with colorectal cancer

Activated T regulatory (Treg) cells are potent suppressors that mediate immune tolerance. We investigated the relationship between activated Treg cells and the progression of human colon cancer. We designed a cross‐sectional study of CD4+Foxp3+ T cells from peripheral blood, primary tumor and nontumor colon tissue of 42 patients with colon cancer and correlated the percentages of different subgroups of Treg cells with colon cancer stage. The phenotypes, cytokine‐release patterns and suppression ability of these Treg cells were analyzed. We found that Treg cells increased significantly in both peripheral blood and cancer tissue. In addition, the Treg cells expressed significantly lower levels of CCR7, CD62L and CD45RA in comparison to normal volunteers. Further dividing Treg cells into subgroups based on Foxp3 and CD45RA expression revealed that both activated Treg cells (Foxp3hiCD45RA−) and nonsuppressive Treg cells (Foxp3loCD45RA−), but not resting Treg cells (Foxp3lowCD45RA+), increased in the peripheral blood and cancer tissue of patients with colon cancer. Only the activated Treg cells expressed significantly higher levels of tumor necrosis factor receptor 2 and cytotoxic T‐cell antigen‐4. Activated Treg cells, however, secreted significantly lower levels of effector cytokines (interleukin‐2, tumor necrosis factor‐α and interferon‐γ) than did resting Treg cells and nonsuppressive cells upon ex vivo stimulation. Activated, but not resting, Treg cells in cancer tissue correlated with tumor metastases. In summary, we confirmed that activated Treg cells are a distinct subgroup with effector memory phenotype and fully functional regulatory activity against human colorectal cancer immunity.

Oral inoculation of probiotics Lactobacillus acidophilus NCFM suppresses tumour growth both in segmental orthotopic colon cancer and extra-intestinal tissue

Modulation of the cellular response by the administration of probiotic bacteria may be an effective strategy for preventing or inhibiting tumour growth. We orally pre-inoculated mice with probiotics Lactobacillus acidophilus NCFM (La) for 14 d. Subcutaneous dorsal-flank tumours and segmental orthotopic colon cancers were implanted into mice using CT-26 murine colon adenocarcinoma cells. On day 28 after tumour initiation, the lamina propria of the colon, mesenteric lymph nodes (MLN) and spleen were harvested and purified for flow cytometry and mRNA analyses. We demonstrated that La pre-inoculation reduced tumour volume growth by 50·3 %, compared with untreated mice at 28 d after tumour implants (2465·5 (SEM 1290·4) v. 4950·9 (SEM 1689·3) mm³, P<0·001). Inoculation with La reduced the severity of colonic carcinogenesis caused by CT-26 cells, such as level of colonic involvement and structural abnormality of epithelial/crypt damage. Moreover, La enhanced apoptosis of CT-26 cells both in dorsal-flank tumour and segmental orthotopic colon cancer, and the mean counts of apoptotic body were higher in mice pre-inoculated with La (P<0·05) compared with untreated mice. La pre-inoculation down-regulated the CXCR4 mRNA expressions in the colon, MLN and extra-intestinal tissue, compared with untreated mice (P<0·05). In addition, La pre-inoculation reduced the mean fluorescence index of MHC class I (H-2Dd, -Kd and -Ld) in flow cytometry analysis. Taken together, these findings suggest that probiotics La may play a role in attenuating tumour growth during CT-26 cell carcinogenesis. The down-regulated expression of CXCR4 mRNA and MHC class I, as well as increasing apoptosis in tumour tissue, indicated that La may be associated with modulating the cellular response triggered by colon carcinogenesis.

Effector/Memory but Not Naive Regulatory T Cells Are Responsible for the Loss of Concomitant Tumor Immunity

The phenomenon of concomitant tumor immunity involves a tumor-bearing host rejecting another similar tumor at a distant site and suggests the existence of tumor-specific immunity. Loss of this immunity may contribute to tumor metastasis. However, mechanisms underlying the loss of concomitant immunity are largely unknown. We set up a concomitant tumor immunity model in which this immunity is gradually lost as the primary tumor progresses. We found that CD8+ T cells, especially tumor-infiltrating CD8+ T cells, from mice that lost concomitant tumor immunity, possessed potent antitumor properties and strongly expressed effector molecules. Furthermore, effector/memory regulatory T cells (Treg cells, CD103+CD4+Foxp3+ T cells) increased as the primary tumor progressed. They initially accumulated around the tumor and in the spleen at later points. Not only did these cells more greatly express killing molecules, they also suppressed the functions of tumor-bearing CD8+ T cells in vitro and in vivo. Finally, we show that these effector/memory Treg cells inhibit concomitant tumor immunity in vivo. Taken together, data suggest that effector/memory Treg cells are responsible for the loss of concomitant tumor immunity associated with tumor progression.