Xuefen Li

Effect of telbivudine therapy on the cellular immune response in chronic hepatitis B

Weak T-cell reactivity to the hepatitis B virus (HBV) is believed to be the dominant cause of chronic HBV infection. Several lines of experimental evidence suggest that treatment with telbivudine increases the rate of HBV e antigen (HBeAg) loss, undetectable HBV DNA, and normalization of serum alanine aminotransferase (ALT) in chronic hepatitis B patients (CHB). However, it is still unclear how early antiviral therapy affects cellular immune responses during sustained telbivudine treatment. In order to investigate this issue, we measured detailed prospective clinical, virological, and biochemical parameters, and we examined the frequency of T cell subgroups as well as the ability of peripheral blood mononuclear cells (PBMC) to respond to stimuli at five protocol time points for 51 CHB patients who received telbivudine therapy for one year. The preliminary data from this study revealed that effective-treated patients showed an increased frequency of peripheral blood CD4(+)T lymphocytes, an augmented proliferative response of HBV-specific T-cells to the hepatitis B core antigen (HBcAg), and the induction of cytokines, such as interferon gamma (IFN-γ), tumour necrosis factor alpha (TNF-α) release at the site of infection compared to non-responsive patients. Enhanced HBV-specific T-cell reactivity to telbivudine therapy, which peaked at treatment week 12, was confined to a subgroup of effective-treated patients who achieved greater viral suppression.

Serotypes, genotypes and antimicrobial resistance patterns of human diarrhoeagenic Escherichia coli isolates circulating in southeastern China

Diarrhoeagenic Escherichia coli (DEC) infection is a major health problem in developing countries. The prevalence and characteristics of DEC have not been thoroughly investigated in China. Consecutive faecal specimens from outpatients with acute diarrhoea in nine sentinel hospitals in southeastern China were collected from July 2009 to June 2011. Bacterial and viral pathogens were detected by culture and RT-PCR, respectively. DEC isolates were further classified into five pathotypes using multiplex PCR. The O/H serotypes, sequence types (STs) and antimicrobial susceptibility profiles of the DEC isolates were determined. A total of 2466 faecal specimens were collected, from which 347 (14.1%) DEC isolates were isolated. DEC was the dominant bacterial pathogen detected. The DEC isolates included 217 EAEC, 62 ETEC, 52 EPEC, 14 STEC, one EIEC and one EAEC/ETEC. O45 (6.6%) was the predominant serotype. Genotypic analysis revealed that the major genotype was ST complex 10 (87, 25.6%). Isolates belonging to the serogroups or genotypes of O6, O25, O159, ST48, ST218, ST94 and ST1491 were highly susceptible to the majority of antimicrobials. In contrast, isolates belonging to O45, O15, O1, O169, ST38, ST226, ST69, ST31, ST93, ST394 and ST648 were highly resistant to the majority of antimicrobials. DEC accounted for the majority of bacterial pathogens causing acute diarrhoea in southeastern China, and it is therefore necessary to test for all DEC, not only the EHEC O157:H7. Some serogroups or genotypes of DEC were highly resistant to the majority of antimicrobials. DEC surveillance should be emphasized.

Simultaneous Detection of Influenza A, Influenza B, and Respiratory Syncytial Viruses and Subtyping of Influenza A H3N2 Virus and H1N1 (2009) Virus by Multiplex Real-Time PCR

ABSTRACT A multiplex real-time PCR assay was developed to simultaneously detect and discriminate influenza A virus subtypes, including novel H1N1 (2009) and seasonal H3N2 virus, influenza B virus, and respiratory syncytial virus (RSV) in a single test tube, with detection sensitivity and specificity of 99% and 100%, respectively, for the four pathogens.

Dynamic variations in the peripheral blood lymphocyte subgroups of patients with 2009 pandemic H1N1 swine-origin influenza A virus infection

BackgroundNovel Influenza A (H1N1) is an acute respiratory infectious disease. Animal experiments indicated that when H1N1 virus infected early hosts, it showed strong CD4+, CD8+, and CD4+CD25+ T cell reactions. The aim of this study was to investigate the dynamic fluctuations of the peripheral blood lymphocyte subgroups in patients infected with H1N1 swine-origin influenza A virus (S-OIV).MethodsThe frequency of T cells, B cells, natural killer (NK) cells, and regulatory T cells (Treg) in 36 severe H1N1 and 40 moderate H1N1 patients were detected at different periods by flow cytometry. In parallel, serum cytokines were detected by enzyme-linked immunosorbent assay and C-reactive protein (CRP) was analyzed through an image-type automatic biochemical analyzer. In addition, 20 healthy volunteers, who were not infected with 2009 H1N1 virus, were selected as controls.ResultsThe frequency of NK cells were decreased in all cases and CD19+ B cells were increased in severe cases than those of the controls. At 1-2d from onset, the frequency of CD4+ and CD4+CD25+ T cells in moderate cases was higher than in the severe cases. Serum cytokines, specifically IL-2, IL-4, IL-6, IL-10, and IFN-γ exhibited no significant change both in the moderate and the severe cases during the whole monitoring process. In the early stage of the disease, serum CRP levels in the severe and moderate groups were significantly higher than that in the control group.ConclusionsPatients showed different lymphocyte subgroup distributions between mild and severe cases, which might affect the incidence and development of 2009 H1N1.

Plasma gelsolin levels and 1-year mortality after first-ever ischemic stroke

PURPOSE Plasma gelsolin depletion has been associated with poor outcome of critically ill patients. We sought to investigate change in plasma gelsolin level after ischemic stroke and to evaluate its relation with disease outcome. MATERIALS AND METHODS Fifty healthy controls and 172 patients with first-ever ischemic stroke were included. Plasma samples were obtained within 24 hours from stroke onset. Its concentration was measured by enzyme-linked immunosorbent assay. RESULTS Plasma gelsolin level in stroke patients was significantly decreased compared with healthy controls. A multivariate analysis showed that plasma gelsolin level was an independent predictor for 1-year mortality (odds ratio, 0.945; 95% confidence interval [CI], 0.918-0.974; P = .0002) and negatively associated with National Institutes of Health Stroke Scale (NIHSS) score (t = -4.802, P < .001) and plasma C-reactive protein level (t = -4.197, P < .001). A receiver operating characteristic curve identified that a baseline plasma gelsolin level less than 52.0 mg/L predicted 1-year mortality of patients with 73.0% sensitivity and 65.2% specificity (area under curve [AUC], 0.738; 95% CI, 0.666-0.802). The predictive value of the gelsolin concentration was similar to that of NIHSS score (AUC, 0.742; 95% CI, 0.670-0.806; P = .940). Gelsolin improved the AUC of NIHSS score to 0.814 (95% CI, 0.747-0.869; P = .032). CONCLUSIONS Plasma gelsolin level is a useful, complementary tool to predict mortality after ischemic stroke.

Current perspectivesin pathogenesis and antimicrobial resistance of enteroaggregative Escherichia coli

Enteroaggregative Escherichia coli (EAEC) is an emerging pathogen that causes acute and persistent diarrhea in children and adults. While the pathogenic mechanisms of EAEC intestinal colonization have been uncovered (including bacterial adhesion, enterotoxin and cytotoxin secretion, and stimulation of mucosal inflammation), those of severe extraintestinal infections remain largely unknown. The recent emergence of multidrug resistant EAEC represents an alarming public health threat and clinical challenge, and research on the molecular mechanisms of resistance is urgently needed.

Detection of a novel avian influenza A (H7N9) virus in humans by multiplex one-step real-time RT-PCR assay

BackgroundA novel avian influenza A (H7N9) virus emerged in eastern China in February 2013. 413 confirmed human cases, including 157 deaths, have been recorded as of July 31, 2014.MethodsClinical specimens, including throat swabs, sputum or tracheal aspirates, etc., were obtained from patients exhibiting influenza-like illness (ILIs), especially from those having pneumonia and a history of occupational exposure to poultry and wild birds. RNA was extracted from these samples and a multiplex one-step real-time RT-PCR assay was developed to specifically detect the influenza A virus (FluA). PCR primers targeted the conserved M and Rnase P (RP) genes, as well as the hemagglutinin and neuraminidase genes of the H7N9 virus.ResultsThe multiplex assay specifically detected the avian H7N9 virus, and no cross-reaction with other common respiratory pathogens was observed. The detection limit of the assay was approximately 0.05 50% tissue culture infective doses (TCID50), or 100 copies per reaction. Positive detection of the H7N9 virus in sputum/tracheal aspirates was higher than in throat swabs during the surveillance of patients with ILIs. Additionally, detection of the matrix (M) and Rnase P genes aided in the determination of the novel avian H7N9 virus and ensured the quality of the clinical samples.ConclusionsThese results demonstrate that the multiplex assay detected the novel avian H7N9 virus with high specificity and sensitivity, which is essential for the early diagnosis and treatment of infected patients.

Cellular immune response in patients with chronic hepatitis B virus infection

Hepatitis, cirrhosis and hepatocellular carcinoma caused by hepatitis B virus (HBV) infection has threatening human health seriously. As HBV is a kind of non-cytotoxic virus, host immune response plays a vital role in pathogenesis and clinical outcomes of hepatitis B. Multiple immune cells (e.g., including cytotoxic T lymphocytes, regulatory T cells, natural killer cells, dendritic cells) are important in the immune regulation of HBV infection. Therefore, focusing on the activation states of immune cells may provide new evidences and strategies for determining immune status of HBV infectors, monitoring progression of diseases and predicting efficacy of antiviral treatment.

Changes of Costimulatory Molecule CD28 on Circulating CD8+ T Cells Correlate with Disease Pathogenesis of Chronic Hepatitis B

Costimulatory signals are critical for antiviral immunity. The aim of this study was to evaluate the change of costimulatory molecule CD28 on circulating CD8+ T cells in chronic hepatitis B patients (CHB). Seventy CHB patients and fifty-six healthy controls were included, and forty-eight CHB patients were recruited for 52 weeks of longitudinal investigation. The proportions of circulating CD8+CD28+ and CD8+CD28− subpopulations were determined by flow cytometry, and the CD8+CD28+/CD8+CD28− T cells ratio was calculated. Compared with the subpopulation in healthy controls, high proportions of CD8+CD28− subpopulation were observed in CHB patients. Similarly, the CD8+CD28+/CD8+CD28− T cells ratio was significantly decreased in CHB patients compared with healthy controls and correlated significantly with hepatitis B virus (HBV) loads. High proportions of CD8+CD28− subpopulation and low CD8+CD28+/CD8+CD28− T cells ratio were observed in hepatitis B e antigen- (HBeAg-) positive individuals as compared with that in HBeAg-negative subjects. A significant decrease in CD8+CD28− subpopulation, increase in CD8+CD28+ subpopulation, and CD8+CD28+/CD8+CD28− T cells ratio were seen in those patients who received efficient antiviral therapy. Thus, aberrant CD28 expression on circulating CD8+ T cells and the CD8+CD28+/CD8+CD28− T cells ratio reflect the dysregulation of T cell activation and are related to the pathogenesis of chronic HBV infection.

Effect of regulatory T cells and adherent cells on the expansion of HBcAg-specific CD8+ T cells in patients with chronic hepatitis B virus infection.

Patients with chronic HBV infection show poor immune response to HBV-specific CD8+ T cells. Several studies demonstrate that regulatory T cells (Treg) and dendritic cells (DC) are important to maintain peripheral immune tolerance. In this study, we investigated the effects of CD4+CD25+Treg and/or the adherent cells (AC) on the proliferation of HBc18-27-specific CD8+ T cells (c18-27-CD8Ts) in response to in vitro stimulation. The frequency of c18-27-CD8Ts in four different mixed leukocyte reactions (MLRs) were analyzed using an HLA-A2-HBc18-27 tetramer. The data indicated that the median percentage of c18-27-CD8Ts in four different MLRs were significant difference in patients with chronic HBV infection. Our results showed that Treg and/or AC might suppress the frequency of HBc18-27-specific CD8+ T cell proliferation in response to in vitro stimulation in chronic HBV patients, and AC might be more effective than Treg.