HIV Infection and TLR Signalling in the Liver

Toll-like Receptor Response to Human Immunodeficiency Virus Type 1 or Co-Infection with Hepatitis B or C Virus: An Overview

Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors that play important roles in the early detection of pathogen-associated molecular patterns and shaping innate and adaptive immune responses, which may influence the consequences of infection. Similarly to other viral infections, human immunodeficiency virus type 1 (HIV-1) also modulates the host TLR response; therefore, a proper understanding of the response induced by human HIV-1 or co-infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), due to the common mode of transmission of these viruses, is essential for understanding HIV-1 pathogenesis during mono- or co-infection with HBV or HCV, as well as for HIV-1 cure strategies. In this review, we discuss the host TLR response during HIV-1 infection and the innate immune evasion mechanisms adopted by HIV-1 for infection establishment. We also examine changes in the host TLR response during HIV-1 co-infection with HBV or HCV; however, this type of study is extremely scarce. Moreover, we discuss studies investigating TLR agonists as latency-reverting agents and immune stimulators towards new strategies for curing HIV. This understanding will help develop a new strategy for curing HIV-1 mono-infection or co-infection with HBV or HCV.

A review of alcohol-pathogen interactions: New insights into combined disease pathomechanisms

Progression of chronic infections to end-stage diseases and poor treatment results are frequently associated with alcohol abuse. Alcohol metabolism suppresses innate and adaptive immunity leading to increased viral load and its spread. In case of hepatotropic infections, viruses accelerate alcohol-induced hepatitis and liver fibrosis, thereby promoting end-stage outcomes, including cirrhosis and hepatocellular carcinoma (HCC). In this review, we concentrate on several unexplored aspects of these phenomena, which illustrate the combined effects of viral/bacterial infections and alcohol in disease development. We review alcohol-induced alterations implicated in immunometabolism as a central mechanism impacting metabolic homeostasis and viral pathogenesis in Simian immunodeficiency virus/human immunodeficiency virus infection. Furthermore, in hepatocytes, both HIV infection and alcohol activate oxidative stress to cause lysosomal dysfunction and leakage and apoptotic cell death, thereby increasing hepatotoxicity. In addition, we discuss the mechanisms of hepatocellular carcinoma and tumor signaling in hepatitis C virus infection. Finally, we analyze studies that review and describe the immune derangements in hepatotropic viral infections focusing on the development of novel targets and strategies to restore effective immunocompetency in alcohol-associated liver disease. In conclusion, alcohol exacerbates the pathogenesis of viral infections, contributing to a chronic course and poor outcomes, but the mechanisms behind these events are virus specific and depend on virus-alcohol interactions, which differ among the various infections.

Reinfection of Transplanted Livers in HCV- and HCV/HIV-Infected Patients Is Characterized by a Different MicroRNA Expression Profile

Background: After liver transplantation, HCV/HIV co-infected patients present, compared to the HCV mono-infected ones, increased HCV viral load, rapid progression to liver fibrosis and higher mortality. Liver biopsies (LB), obtained routinely 6 months after transplantation, represent a unique model to assess the early events related to graft re-infection. Here, we used miRNA sequencing of LB obtained from both HCV-and HCV/HIV-infected recipients, to identify transcriptional profiles able to explain the more severe outcome of these latter. Methods: miRNAs of 3 healthy livers, 3 HCV-LB and 3 HCV/HIV-LB were sequenced by Illumina HiSeq2500 platform. The DIANA-miRPath v3.0 webserver and DIANA-microT-CDS algorithm (v5.0) were used to characterize the functions of differentially expressed (DE-) miRNAs, querying the KEGG and Gene Ontology-Biological Process databases. Results: LB obtained from infected patients were characterized, with respect to controls, by a miRNA profile related to viral infection, immune system signaling and DNA damage in HCV-induced carcinogenesis. Instead, HCV-LB and HCV/HIV-LB differed in the expression of miRNAs involved in immunological and apoptotic processes and in extracellular matrix remodeling. Conclusions: liver reinfection processes are associated with early miRNA changes. Further studies are necessary to establish their prognostic role and possible actionability.

Oncogenic Effects of HIV-1 Proteins, Mechanisms Behind

People living with human immunodeficiency virus (HIV-1) are at increased risk of developing cancer, such as Kaposi sarcoma (KS), non-Hodgkin lymphoma (NHL), cervical cancer, and other cancers associated with chronic viral infections. Traditionally, this is linked to HIV-1-induced immune suppression with depletion of CD4+ T-helper cells, exhaustion of lymphopoiesis and lymphocyte dysfunction. However, the long-term successful implementation of antiretroviral therapy (ART) with an early start did not preclude the oncological complications, implying that HIV-1 and its antigens are directly involved in carcinogenesis and may exert their effects on the background of restored immune system even when present at extremely low levels. Experimental data indicate that HIV-1 virions and single viral antigens can enter a wide variety of cells, including epithelial. This review is focused on the effects of five viral proteins: envelope protein gp120, accessory protein negative factor Nef, matrix protein p17, transactivator of transcription Tat and reverse transcriptase RT. Gp120, Nef, p17, Tat, and RT cause oxidative stress, can be released from HIV-1-infected cells and are oncogenic. All five are in a position to affect "innocent" bystander cells, specifically, to cause the propagation of (pre)existing malignant and malignant transformation of normal epithelial cells, giving grounds to the direct carcinogenic effects of HIV-1.

Modelling hepatotoxicity and antiretroviral therapeutic effect in HIV/HBV coinfection

Enzyme alanine aminotransferase (ALT) elevation which reflects hepatocellular injury is a current challenge in people infected with human immunodeficiency virus (HIV) on antiretroviral therapy (ART). One of the factors that enhance the risk of hepatotoxicity is underlying diseases such as hepatitis caused by hepatitis B virus (HBV). HIV/HBV coinfected patients stand a greater risk of hepatotoxicity because all ART are toxic and liver cells (hepatocytes) that are responsible for metabolising the toxic ART, support all stages of HIV and HBV viral production. Mathematical models coupled with numerical simulations are used in this study with the aim of investigating the optimal combination of ART in HIV/HBV coinfection. Emtricitabine, tenofovir and efavirenz is the optimal combination that maximises the therapeutic effect of therapy and minimises the toxic response to medication in HIV/HBV coinfection.

HBV and HIV viral load but not microbial translocation or immune activation are associated with liver fibrosis among patients in South Africa

Background

Co-infection with HIV negatively impacts the progression of chronic hepatitis B virus (HBV) infection, including causing rapid progression to liver fibrosis. Sub-Saharan Africa represents arguably the most important intersection of high endemicity of both chronic hepatitis B virus (HBV) infection and HIV infection.

Methods

We recruited 46 HBV/HIV-co-infected; 47 HBV-monoinfected; 39 HIV-monoinfected; and 37 HBV/HIV-uninfected patients from Tygerberg Hospital, Cape Town, South Africa. All HIV-infected patients were on antiretroviral therapy for ≥3 months. Liver stiffness measurements were assessed using the Fibroscan (Fibroscan 402, Echosens). Cell-based immunomarkers were measured by flow cytometry. Soluble serum/plasma immunomarkers were measured by Luminex technology and enzyme immunoassays. HIV (COBAS/Ampliprep TaqMan HIV-1) and HBV viral loads (in-house assay) were also performed.

Results

HBV/HIV co-infected patients showed significantly higher levels of immune activation %CD8+/HLA-DR+/CD38+ (median 30%, interquartile range: 17–53) and %CD8+/PD-1 (median 22%, interquartile range: 15–33), p ≤ 0.01 compared to all other study groups. Despite this, the HBV-mono-infected group had the highest proportion of patients with advanced liver fibrosis (≥13 kPa) as measured by Fibroscan (18%). HBV mono-infected patients showed highest expression of most cytokines including IL-17 and basic fibroblastic growth factor. There was significant positive correlation between detectable HIV and HBV viral replication and liver fibrosis but not immune activation or gut translocation.

Discussion

Highly-active antiretroviral therapy, including tenofovir, is effective against both HIV and HBV. Earlier therapy in the co-infected patients may therefore have controlled viral replication leading to better fibrosis scores when compared to HBV mono-infection in this study. On-going HBV and HIV viraemia, rather than microbial translocation or immune activation, appear to be the drivers of liver fibrosis. Moderate to advanced liver fibrosis in HBV-mono-infection may well indicate poor access to screening and treatment of HBV infection.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3115-8) contains supplementary material, which is available to authorized users.

Elevated pre-treatment IL-18 level is associated with HBeAg seroconversion in HIV-HBV coinfection

BACKGROUND

In HBV-infected patients, hepatitis B e antigen (HBeAg) seroconversion is associated with better outcomes. Interleukin-18 (IL-18) controls hepatitis B replication in a mouse model. However, its role in treatment response in HIV-HBV-coinfected patients is unknown.

METHODS

We enrolled 35 treatment-naive, HBeAg-positive, HIV-HBV-coinfected patients. HBV DNA, HIV RNA, CD4⁺ T-cell count, HBV surface antigen (HBsAg) quantification (qHBsAg), HBeAg quantification (qHBeAg) and IL-18 levels were measured prior to, at 24 and 48 weeks of HBV-active combination antiretroviral therapy (cART). Multivariate Poisson regression models with robust standard errors were used to determine factors associated with HBeAg seroconversion.

RESULTS

Twenty-one patients received tenofovir (TDF) + lamivudine (3TC) based cART while 14 patients received 3TC-based cART. After 48 weeks of treatment, 10 patients experienced HBeAg seroconversion. Compared with non-seroconverters, seroconverters had higher median HIV RNA (5.22 versus 4.58 log copies/ml; P=0.030), lower median qHBsAg (3.97 versus 4.76 log IU/ml; P=0.011), lower median qHBeAg (1.61 versus 3.01 log PEIU/ml; P=0.004) and marginally higher median IL-18 (2.70 versus 2.53 log pg/ml; P=0.068) prior to ART. In the multivariate regression, higher baseline IL-18 (adjusted relative risk [aRR] 2.99 per 1 log pg/ml increase; P=0.035), high HIV RNA (aRR 1.84 per 1 log copies/ml; P=0.029) and low qHBeAg (aRR 0.71 per 1 log PEIU/ml; P=0.029) were significantly associated with HBeAg seroconversion.

CONCLUSIONS

In HIV-HBV-coinfected patients with HBeAg positivity, higher IL-18 levels, HIV RNA load, as well as low qHBeAg prior to cART were associated with HBeAg seroconversion.

Modelling Hepatotoxicity of Antiretroviral Therapy in the Liver during HIV Monoinfection

Liver related complications are currently the leading cause of morbidity and mortality among human immunodeficiency virus (HIV) infected individuals. In HIV monoinfected individuals on therapy, liver injury has been associated with the use of antiretroviral agents as most of them exhibit some degree of toxicity. In this study we proposed a mathematical model with the aim of investigating hepatotoxicity of combinational therapy of antiretroviral drugs. Therapy efficacy and toxicity were incorporated in the model as dose-response functions. With the parameter values used in the study, protease inhibitors-based regimens were found to be more toxic than nonnucleoside reverse transcriptase inhibitors-based regimens. In both regimens, the combination of stavudine and zidovudine was the most toxic baseline nucleoside reverse transcriptase inhibitors followed by didanosine with stavudine. However, the least toxic combinations were zidovudine and lamivudine followed by didanosine and lamivudine. The study proposed that, under the same second line regimens, the most toxic first line combination gives the highest viral load and vice versa.