The addition of mycophenolate mofetil for suppressing hepatitis B virus replication in liver recipients who developed lamivudine resistance--no beneficial effect

[Role of cellular metabolism in the control of chronic viral hepatitis]

Hepatitis viruses modify the cellular metabolism of hepatocytes by interacting with specific enzymes such as glucokinase. The metabolic changes induced by viruses can have a direct impact on the innate antiviral response. The complex interactions between viral components, innate immunity, and hepatocyte metabolism explain why chronic hepatitis infections lead to liver inflammation, progressing to cirrhosis, fibrosis, and hepatocellular carcinoma. Metabolic regulators could be used in innovative therapies to deprive viruses of key metabolites and induce an antiviral defense.

Perspectives on Mycophenolate Mofetil in the Management of Autoimmunity

Before becoming a cornerstone in the treatment of numerous immune-mediated diseases, mycophenolate mofetil (MMF) was first introduced as an immunosuppressive agent in transplant immunology and later received the attention of rheumatologists and clinicians involved in the management of autoimmune diseases. MMF is now a widespread immunosuppressive drug for the treatment of several conditions, including lupus nephritis, interstitial lung disease associated with systemic sclerosis, and anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis while being efficacious also as rescue therapy in various orphan diseases, including dermatomyositis and IgA-associated nephropathy. Similarly, case reports or series support a possible use of MMF in other rare autoimmune diseases. Beyond modulating lymphocyte activation, MMF acts on other immune and non-immune cells and these effects may explain the therapeutic profile of this medication. The effects of MMF are broadly characterized by the impact on the immune system and the antiproliferative and antifibrotic changes induced. In this latter case, mechanistic data on fibroblasts may in the future allow to reevaluate the use of MMF in selected patients with inflammatory arthritis or systemic sclerosis. Attention must be paid towards the possible occurrence of adverse events, such as gastrointestinal complaints and teratogenicity, while the risk of infections and cancer related to MMF needs to be further investigated.

What role for cellular metabolism in the control of hepatitis viruses?

Hepatitis B, C and D viruses (HBV, HCV, HDV, respectively) specifically infect human hepatocytes and often establish chronic viral infections of the liver, thus escaping antiviral immunity for years. Like other viruses, hepatitis viruses rely on the cellular machinery to meet their energy and metabolite requirements for replication. Although this was initially considered passive parasitism, studies have shown that hepatitis viruses actively rewire cellular metabolism through molecular interactions with specific enzymes such as glucokinase, the first rate-limiting enzyme of glycolysis. As part of research efforts in the field of immunometabolism, it has also been shown that metabolic changes induced by viruses could have a direct impact on the innate antiviral response. Conversely, detection of viral components by innate immunity receptors not only triggers the activation of the antiviral defense but also induces in-depth metabolic reprogramming that is essential to support immunological functions. Altogether, these complex triangular interactions between viral components, innate immunity and hepatocyte metabolism may explain why chronic hepatitis infections progressively lead to liver inflammation and progression to cirrhosis, fibrosis and hepatocellular carcinoma (HCC). In this manuscript, we first present a global overview of known connections between the innate antiviral response and cellular metabolism. We then report known molecular mechanisms by which hepatitis viruses interfere with cellular metabolism in hepatocytes and discuss potential consequences on the innate immune response. Finally, we present evidence that drugs targeting hepatocyte metabolism could be used as an innovative strategy not only to deprive viruses of key metabolites, but also to restore the innate antiviral response that is necessary to clear infection.

Investigational drugs with dual activity against HBV and HIV (Review)

Chronic hepatitis B (CHB) and acquired immunodeficiency syndrome (AIDS) are global public health problems that pose a significant health burden. Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) coinfection is common, as these viruses have similar transmission routes, such as blood transmission, sexual transmission and mother-to-child transmission. Coinfection frequently leads to accelerated disease progression. For individuals coinfected with HIV/HBV, combination antiretroviral therapy containing dual anti-HBV drugs is recommended. Certain studies have also indicated the benefits of antiretroviral drugs with anti-HBV activity in patients with coinfection. A total of four Food and Drug Administration-approved HIV drugs also have anti-HBV activity; namely, emtricitabine, lamivudine, tenofovir disoproxil fumarate and tenofovir alafenamide, which are all nucleoside reverse transcriptase inhibitors. However, various issues, including drug resistance and side effects, limit their application. Therefore, it is necessary to develop more drugs with dual activity against HBV and HIV. The present review outlines the mechanisms, safety and efficacy of certain drugs that have been investigated for this purpose.

Reactivation of hepatitis B virus infection in rheumatic diseases: risk and management considerations

In patients with rheumatic diseases undergoing immunosuppressive treatment, hepatitis B virus reactivation (HBVr) has been long recognized as a major treatment-related adverse event with substantial morbidity and mortality. Because HBVr is easily preventable with appropriate screening and monitoring strategies, and, when indicated, prophylactic antiviral treatment, awareness of this complication is of the utmost importance, especially in the era of biologic treatments. As a condition, it continues to be topical, in view of the emergence of novel classes of immunosuppressive drugs (i.e. Janus kinase inhibitors) acquiring licenses for a variety of rheumatic diseases. The class-specific risk of these agents for HBVr has not yet been determined. Moreover, ambiguity still exists for the management of patients planned to be treated with traditional agents, such as cyclophosphamide and glucocorticoids, particularly in the setting of resolved HBV infection. Clinicians in the field of rheumatic diseases should be tailoring their practice according to the host's profile and treatment-specific risk for HBVr. In this review, the authors attempt to critically review the existing literature and provide practical advice on these issues.

Effect of maintenance immunosuppressive drugs on virus pathobiology: evidence and potential mechanisms

Recent evidence suggesting a potential anti-CMV effect of mTORis is of great interest to the transplant community. However, the concept of an immunosuppressant with antiviral properties is not new, with many accounts of the antiviral properties of several agents over the years. Despite these reports, to date, there has been little effort to collate the evidence into a fuller picture. This manuscript was developed to gather the evidence of antiviral activity of the agents that comprise a typical immunosuppressive regimen against viruses that commonly reactivate following transplant (HHV1 and 2, VZV, EBV, CMV and HHV6, 7, and 8, HCV, HBV, BKV, HIV, HPV, and parvovirus). Appropriate immunosuppressive regimens posttransplant that avoid acute rejection while reducing risk of viral reactivation are also reviewed. The existing literature was disparate in nature, although indicating a possible stimulatory effect of tacrolimus on BKV, potentiation of viral reactivation by steroids, and a potential advantage of mammalian target of rapamycin (mTOR) inhibition in several viral infections, including BKV, HPV, and several herpesviruses.

Risk factors and outcomes of Staphylococcus aureus infections after small bowel and multivisceral transplantation

BACKGROUND

No studies have evaluated the risk factors and outcomes of Staphylococcus aureus (SA) infections in small bowel (SBT) and multivisceral (including small bowel) transplantation (MVT).

METHODS

SBT and MVT recipients with SA infections (22 cases) were retrospectively identified and compared with matched non-SA-infected recipient controls (44). The characteristics were compared with Friedman and Cochran-Mantel-Haenszel tests. Conditional logistic regression analysis was performed to identify risk factors, and Kaplan-Meier curve and Cox proportional hazard model were performed for survival analysis.

RESULTS

The median age was 2.07 years (range, 0.76-54.04). Forty-three percent of the first SA infections were bloodstream infections, 30% lung infections, and 26% surgical site infections; 36% of these isolates were methicillin-resistant SA. Median time (days) to surgical site infections (41.0; range, 0-89) was significantly shorter than that to lung infections (266; range, 130-378) (P = 0.01). By univariate analysis, it was found that cases were more likely to have cytomegalovirus (CMV) sero-mismatch (odds ratio [OR] = 3.03 [95% confidence interval, 0.88-10.43]; P = 0.08), and controls were more likely to receive mycophenolate mofetil (MMF) treatment (0.09 [0.001-0.82]; P = 0.03). By multivariable analysis, patients with CMV sero-mismatch were found to have higher odds of developing SA infection (OR, 2.92; P = 0.085), whereas MMF had a protective effect (OR, 0.08; P = 0.031), adjusting for matched criteria. SA cases had shorter survival than controls (mean survival, 28.5 vs. 45.8 months [P = 0.04]) and were 2.18 times more likely to die (1.02-4.67, P = 0.04).

CONCLUSIONS

SA infections were associated with a significant shorter survival time and higher risk of death. The presence of CMV sero-mismatch and the absence of MMF treatment were found to be the risk factors for SA infections after SBT and MVT.

Mycophenolate mofetil: effects on cellular immune subsets, infectious complications, and antimicrobial activity

Mycophenolate mofetil (MMF) is one of the most frequently used immunosuppressive drugs in solid organ transplant recipients. MMF is an inhibitor of inosine-5'-monophosphate, and is able to preferentially inhibit B-cell and T-cell function. The immunosuppressive abilities of MMF have made it one of the most successful anti-rejection drugs in transplant patients, but patients also appear to have increased susceptibility to infections, specifically cytomegalovirus and BK virus. Despite its association with an increased risk of infection, MMF has also exhibited antimicrobial activity against pathogens including hepatitis C, Pneumocystis jirovecii, and human immunodeficiency virus. A thorough understanding of the functions of MMF on the immune system and interaction with infectious pathogens could be helpful in implementing preventative strategies against opportunistic infections in transplant patients.

The use of mycophenolate mofetil in liver transplant recipients

Mycophenolate mofetil is an important drug in the modern immunosuppressive arsenal. Mycophenolate mofetil is the semisynthetic morpholinoethyl ester of mycophenolate acid. Mycophenolate acid prevents T and B cell proliferation by specifically inhibiting a purine pathway required for lymphocyte division. This paper extensively reviews the experience of mycophenolate mofetil use in liver transplant recipients. In randomised trials, mycophenolate mofetil decreased the rate of acute rejection after liver transplantation, without a significant increase of septic complications. However, so far, there are no data indicating that mycophenolate mofetil increases liver transplant patient or graft survivals. Mycophenolate mofetil is interesting because of its particular side effects profile, which is very different from the other immunosuppressants. The absence of mycophenolate mofetil nephrotoxicity is of specific interest in liver recipients with impairment of renal function. The monitoring of mycophenolate acid area under the concentration time curve might be interesting to limit side effects and provide better clinical efficacy but the exact role of mycophenolate acid monitoring in liver recipients has yet to be further evaluated in large series.

Immunosuppression in hepatitis B virus and hepatitis C virus transplants: special considerations

The management of the immunosuppression treatment must take account its consequences on viral replication. Such treatment operates on the emerging balance between the recurrence of the virus on the graft and the immune response of the host. Randomized and prospective trials are currently ongoing with the purpose of determining the opportunity and relevance of each immunosuppressive agent in the treatment. In HBV patients, good control of HBV reinfection by prophylactic strategies using HBIG, lamivudine, or both have decreased the impact of immunosuppression on HBV recurrence. In contrast, HCV recurrence is now a major problem. The mechanisms of viral recurrence need to be deepened thus requiring new studies. The absence of in vitro and in vivo systems to study HCV reinfection is a lack in the comprehension of the relation between HCV and immunosuppression. It will allow adapting the effectiveness of the immunosuppression treatment. The treatment's primary target is to avoid graft rejection, and its secondary objective is to limit the risk of viral recurrence.