Silvia Lee

Association of Increased Hepatitis C Virus (HCV)–Specific IgG and Soluble CD26 Dipeptidyl Peptidase IV Enzyme Activity with Hepatotoxicity after Highly Active Antiretroviral Therapy in Human Immunodeficiency Virus–HCV-Coinfected Patients

Hepatotoxicity was investigated, using plasma collected before and during treatment, in 16 human immunodeficiency virus (HIV)-hepatitis C virus (HCV)-coinfected patients who responded to highly active antiretroviral therapy (HAART), during a retrospective longitudinal study. Eleven patients experienced hepatotoxicity (i.e., a >3-fold increase in alanine aminotransferase level) while receiving HAART, including 4 patients with clinical hepatitis. Control subjects were 5 patients without hepatotoxicity. Markers of HCV-specific immune responses (HCV core-specific immunoglobulin G [IgG] antibody), T cell activation (soluble [s] CD26 dipeptidyl peptidase IV [DPP IV] enzyme activity), and inflammation (nitrate/nitrite and soluble tumor necrosis factor receptor I [sTNFRI] levels) were correlated with liver damage and immune reconstitution. All patients with hepatotoxicity had increased HCV core-specific IgG antibody and sCD26 (DPP IV) activity but did not have increased nitrate/nitrite or sTNFRI levels. Hepatotoxicity without clinical hepatitis was associated with increased CD8 T cell counts. Thus, hepatotoxicity in HIV-HCV-coinfected patients who respond to HAART is associated with increased HCV-specific immune responses and T cell activation.

An evaluation of serum soluble CD30 levels and serum CD26 (DPPIV) enzyme activity as markers of type 2 and type 1 cytokines in HIV patients receiving highly active antiretroviral therapy

This study evaluates serum CD26 (dipeptidyl peptidase IV, DPPIV) enzyme activity and serum levels of soluble CD30 as markers of T1 and T2 cytokine environments in HIV patients who achieved immune reconstitution after highly active antiretroviral therapy (HAART). Patients who had experienced inflammatory disease associated with pre‐existent opportunistic infections after HAART (immune restoration diseases, IRD) were considered separately. Serum sCD30 levels and CD26 (DPPIV) enzyme activity were compared with IFN‐γ production by PBMC cultured with cytomegalovirus (CMV) antigen in controls and patient groups. High sCD30 levels were associated with low IFN‐γ production after antigenic stimulation in control subjects and, to a lesser extent, in immune reconstituted HIV patients. There was no association between serum CD26 (DPPIV) enzyme activity and IFN‐γ production or sCD30 levels. Serum sCD30 levels and CD26 (DPPIV) enzyme activity were significantly increased in immune reconstituted patients with high HIV viral loads. Patients who had experienced CMV retinitis as an IRD had significantly higher sCD30 levels than all other patient groups. Hence, high sCD30 levels may be a marker of a T2 cytokine environment in HIV patients with immune reconstitution and are associated with higher HIV viral loads and a history of CMV associated IRD.

Restoration of CD4 T-cell responses to cytomegalovirus is short-lived in severely immunodeficient HIV-infected patients responding to highly active antiretroviral therapy.

To define the level of pathogen‐specific immune reconstitution persisting over 3 to 5 years of highly active antiretroviral therapy (HAART) in HIV‐infected patients who began therapy with CD4 T‐cell counts below 50 cells/μL.

CD31 (PECAM-1) is a marker of recent thymic emigrants among CD4 + T-cells, but not CD8 + T-cells or γδ T-cells, in HIV patients responding to ART

Some severely immunodeficient HIV patients experience poor recovery of CD4+ T‐cell counts on antiretroviral therapy (ART). Evaluation of the function of thymopoiesis in T‐cell production in individual patients requires a simple marker of T‐cells that have recently emigrated from the thymus. Here, we address whether expression of CD31 on CD4+ T‐cells, CD8+ T‐cells, regulatory T‐cells and γδ T‐cells correlates with other indicators of thymus function. Adult HIV‐1 patients (n=27) with nadir CD4+ T‐cell counts <100 per μl and a sustained virological response to ART and healthy controls (n=23) were studied. CD31 expression was assessed by flow cytometry, T‐cell receptor excision circles content by real‐time PCR and thymic volume by spiral computed tomography. Proportions of CD4+ T‐cells expressing CD45RA and CD31 declined with age in HIV patients (P=0.03) and healthy controls (P<0.0001), and correlated directly with other markers of thymus function. In controls, proportions of CD8+ T‐cells expressing CD45RA and CD31 declined with age (P=0.003) and correlated directly with some markers of thymus function, but this was not seen in HIV patients. Proportions of CD45RA+ CD31+ γδ T‐cells were higher in patients than controls (P=0.007) and did not correlate with thymus volume. In controls, proportion of γδ T‐cells co‐expressing CD45RA and CD31 increased with age (P=0.002). These data support the use of CD31 as a marker of recent thymic origin in CD4+ T‐cells, but not CD8+ T‐cells in HIV patients receiving ART. In such patients, CD31 expression is unlikely to indicate thymic origin in γδ T‐cells.

Toll-like receptor (TLR) expression on CD4+ and CD8+ T-cells in patients chronically infected with hepatitis C virus

Toll-like receptor (TLR) expression on T-cells and the signalling pathways that lead to the production of cytokines may limit antigen-specific T-cell responses. Here, expression of TLR and retinoic acid inducible gene I (RIG-I) on T-cells were evaluated in patients chronically infected with hepatitis C virus (HCV), before and during pegylated interferon-alpha and ribavirin therapy. Expression of TLR2,3,4,7,9 and retinoic acid inducible gene (RIG)-I on different CD4(+) and CD8(+) T-cell sub-populations (naïve: CD45RA(+)CD57(-); central memory: T(CM) CD45RA(-)CD57(-); effector memory: T(EM) CD45RA(-)CD57(+) and terminally differentiated effector memory: T(EMRA) CD45RA(+)CD57(+)) were measured by flow cytometry. TLR7, TLR9 and RIG-I expression on CD4(+) T-cells and RIG-I expression on CD8(+) T-cells was higher in patients than healthy controls. Therapy increased expression of TLR2, TLR4 and TLR9 and this was observed for all T-cell sub-populations. Evaluation of TLR expression at baseline did not identify patients able to achieve sustained virological response following therapy.

IL-23 and IFN-γ deficiency in immunodeficient HIV patients who achieved a long-term increase in CD4 T-cell counts on highly active antiretroviral therapy

The pathogenesis of HIV infection and the susceptibility to opportunistic infections has been associated with poor type 1 cytokine production. In severely immunodeficient HIV patients who achieved increased CD4 T-cell counts on longterm highly active antiretroviral therapy, we observed reduced expression of IL-23p19 and IFN-gamma messenger RNA. Impaired IL-23-induced IFN-gamma production by memory T cells might thus contribute to opportunistic infections in a minority of patients with substantial CD4 T-cell recovery.

RUNX3 is a novel negative regulator of oncogenic TEAD-YAP complex in gastric cancer.

Runt-related transcription factor 3 (RUNX3) is a well-documented tumour suppressor that is frequently inactivated in gastric cancer. Here, we define a novel mechanism by which RUNX3 exerts its tumour suppressor activity involving the TEAD–YAP complex, a potent positive regulator of proliferative genes. We report that the TEAD–YAP complex is not only frequently hyperactivated in liver and breast cancer, but also confers a strong oncogenic activity in gastric epithelial cells. The increased expression of TEAD–YAP in tumour tissues significantly correlates with poorer overall survival of gastric cancer patients. Strikingly, RUNX3 physically interacts with the N-terminal region of TEAD through its Runt domain. This interaction markedly reduces the DNA-binding ability of TEAD that attenuates the downstream signalling of TEAD–YAP complex. Mutation of RUNX3 at Arginine 122 to Cysteine, which was previously identified in gastric cancer, impairs the interaction between RUNX3 and TEAD. Our data reveal that RUNX3 acts as a tumour suppressor by negatively regulating the TEAD–YAP oncogenic complex in gastric carcinogenesis.

Immunological markers predicting outcome in patients with hepatitis C treated with interferon-α and ribavirin

Type 1 (T1) cytokine responses are required for the clearance of hepatitis C virus by cytotoxic T lymphocytes, but can promote liver damage. Interferon‐α (IFNα) can be expected to promote T1 cytokine responses, so treatment outcome may depend on the T1/T2 cytokine environment and levels of immune activation at baseline. This model was tested by monitoring immunological markers in a pilot study of treatment naïve patients given IFNα2b and ribavirin, with the aim of finding markers that predict virological outcome. Soluble (s) CD26/dipeptidyl peptidase IV enzyme activity and levels of sCD30, bioavailable IL‐6, sTNF‐RI, IL‐1ra and nitrite/nitrate (NO2 −/NO3 −) were measured. Levels of IL‐1ra and bioavailable IL‐6 were lower in patients than controls and did not change with therapy. Treatment decreased sCD26/dipeptidyl peptidase IV enzyme activities and sCD30 levels and increased NO2 −/NO3 − levels. High baseline sCD30 levels predicted an early (P = 0.008) and sustained (P = 0.03) virological response to therapy, suggesting treatment may be more effective in patients with a predominant T2 profile.

The Use of Humoral Responses as a Marker of CMV Burden in HIV Patients on ART Requires Consideration of T-Cell Recovery and Persistent B-Cell Activation

Objectives. Elevated humoral responses to cytomegalovirus (CMV) associate with increased risk of cardiovascular disease (CVD) in HIV patients on antiretroviral therapy (ART). To better understand the persistence of CMV humoral responses in relation to CVD, we determined trends in CMV antibody levels over the first 10 years on ART. Design. We describe longitudinal analyses of plasma from 13 HIV patients commencing ART with <210 CD4 T-cells/µL and 27 controls. Antibodies reactive with CMV (fibroblast lysate, gB and IE-1 antigens), EBV-VCA, and HIVgp41 were quantitated. B-cell activation was assessed via total IgG and sBAFF. Inflammation was assessed via sTNF-RI and sCD14. Results. Amongst CMV seropositive HIV patients, levels of antibody reactive with CMV (P = 0.03) and EBV-VCA (P = 0.02) peaked after 1 year on ART. Levels of total IgG, sCD14, and sTNF-RI declined to approximate those in controls after 10 years, but sBAFF (P = 0.0002), EBV-VCA (P = 0.001), and CMV (P = 0.0004) antibodies remained elevated. A strong correlation between sBAFF and CMVgB antibody was seen at 10 years (R = 0.93, P = 0.0009) and verified in a second cohort. Conclusions. CMV antibody titres peak on ART and remain high. A correlation between CMV antibody and sBAFF suggests a role for HIV-induced B-cell pathology that may affect its use as a marker of CMV burden.

Increased Proportion of the CD56 bright NK Cell Subset in Patients Chronically Infected With Hepatitis C Virus (HCV) Receiving Interferon-α and Ribavirin Therapy

Natural killer (NK) cells are implicated in the regulation of a protective immune response in patients chronically infected with hepatitis C virus (HCV), but effects of interferon‐α/ribavirin therapy on NK cell subsets and the consequences of viral clearance during therapy remain unclear. Samples were collected from chronically infected patients (n = 34) at baseline and from a subset after 3–10 months on pegylated interferon‐α and ribavirin therapy (n = 19). NK cells present in cryopreserved PBMC were characterized by flow cytometry. Before therapy, the frequency of CD3−CD56+ NK cells was lower in patients than uninfected controls. Therapy increased proportions of CD56bright NK cells. Frequencies of CD56dim NK cells declined slightly while perforin and CD16 expression on CD56dim NK cells decreased compared to baseline samples. Evaluation of NK cell subsets at baseline did not identify patients able to achieve sustained virological response following therapy. However, therapy may promote the expansion of NK cells able to produce interferon‐γ, while minimizing cytotoxicity to limit liver damage. J. Med. Virol. 82:568–574, 2010.