Prevention of hepatitis B virus recurrence after liver transplantation

Incisional hernia repair after kidney transplantation in a tertiary high-volume center: outcomes from a 10-year retrospective cohort study

BACKGROUND AND AIM

Incisional hernia (IH) after Kidney Transplantation (KT) is a challenging complication due to both technical reasons and patients' complexity. Data regarding outcomes of hernia repair in KT recipients are uncertain, since the biggest part of previous papers focused on risk factors for incisional hernia occurrence and not on its outcomes. Aim of the study was to focus on risk factors for incisional hernia recurrence after surgical repair in KT recipients.

METHODS

Data regarding all consecutive patients undergoing kidney transplantations from January 2011 until September 2020 in Montpellier University Hospital were retrospectively collected from a single institutional database.

RESULTS

After a median follow-up of 48 months (IQR_25-75 31-59), data from 1546 consecutive KT were collected. 83 patients underwent 99 incisional hernia surgeries after KT, with 14 patients that had one recurrence (14.4%) and 2 patients that experienced two recurrences (2.4%). Total recurrence rate was 16.8%. At univariate analysis, the only factor associated with an incisional hernia recurrence was having undergone to at least one previous abdominal surgery other than KT (p value 0.002). Overall morbidity was 15% (n = 15), with most of complications classified as mild (59%). No mortality related to incisional hernia repair occurred.

CONCLUSION

IHs after KT represent an important condition. Its surgical management is challenging due to its anatomical complexity and patient's status. This is the largest sample size in the literature of patients treated for IH after KT and it shows that a previous surgery other than the KT is a risk factor for hernia recurrence after surgical repair, without regarding surgical technique or other comorbidity and therapeutical factors.

Passive Monoclonal and Polyclonal Antibody Therapies

Passive antibody therapies have a long history of use. In the 19th century, antibodies from xenographic sources of polyclonal antibodies were used to treat infections (diphtheria). They were used often as protection from infectious agents and toxins. Complications related to their use involved development of immune complexes and severe allergic reactions. As a result, human source plasma for polyclonal antibodies became the preferential source for antibodies. They are used to treat infection, remove toxins, prevent hemolytic disease of the newborn, modify inflammatory reactions, and control autoimmune diseases. Continued improvements in processing decreased the transfusion/infusion transmission of infections. In the late 20th century (∼1986), monoclonal antibodies were developed. The first monoclonal antibodies were of xenographic source and were wrought with problems of immunogenicity. These forms of antibodies did not gain favor until chimerization took pace in the mid-1990s and in 1998 two monoclonal antibodies were approved one to treat respiratory syncytial virus and the other for breast cancers. Further development of humanized and then fully human monoclonal antibodies has led to an evolution of therapies with these agents. Monoclonal antibodies are being researched or approved to treat a multitude of diseases to include oncologic, inflammatory, autoimmune, cardiovascular, respiratory, neurologic, allergic, benign hematologic, infections, orthopedic, coagulopathy, metabolic and to decrease morbidity of disease (diminution of pain), modify disease progression, and potentially anatomic development. In this chapter, we will review the history of use of these passive antibody therapies, their mechanism of action, pharmacologic-therapeutic classification, particular medical indication, adverse reactions, and potential future use of these medications.

Tenofovir-emtricitabine therapy for the prevention of hepatitis B recurrence in four patients after liver transplantation

In patients infected with chronic hepatitis B virus (HBV) that goes untreated, therapeutic options are limited once the disease decompensates, and orthotopic liver transplantation is often the only treatment available to save the patient's life. After liver transplantation, combined therapy with hepatitis B immune globulin (HBIG) and a nucleos(t)ide analog is the standard of practice for the prevention of HBV recurrence. Historically, nucleos(t)ide analogs such as lamivudine and adefovir have been used with low-dose HBIG for the prevention of HBV recurrence after liver transplantation. However, these analogs are ineffective when used alone due the emergence of resistance mutations. Newer nucleos(t)ide analogs such as tenofovir disoproxil fumarate have demonstrated higher resistance thresholds and effective viral suppression when paired with low-dose HBIG. In this case series, we evaluated the safety and efficacy of switching four patients from low-dose HBIG plus nucleos(t)ide analog therapy for the prevention of HBV recurrence to a combination tenofovir-emtricitabine regimen. At the end of follow-up, all patients remained hepatitis B surface antigen negative and had HBV DNA levels of less than 10 IU/ml. Additionally, no tenofovir-associated nephrotoxicity was observed among the four patients. Tenofovir-emtricitabine monotherapy in lieu of HBIG plus nucleos(t)ide analog therapy demonstrated prevention of HBV recurrence without tenofovir-associated nephrotoxicity after 9 months of follow-up in all four patients and up to 15 months in one patient.

Dysfunction of splenic macrophages in cirrhotic patients with hypersplenism and HBV infection

BACKGROUND

Hepatitis B virus (HBV) reinfection is a difficult problem to manage after liver transplantation in patients with cirrhosis. This study was designed to investigate the activation type of splenic macrophages in cirrhotic patients with hypersplenism and HBV infection to assess the immune function of splenic macrophages.

METHODS

Fourteen cirrhotic patients with hypersplenism and HBV infection and 6 controls were enrolled in the study. Serum lipopolysaccharide (LPS) was detected with a limulus assay. The differential expression of cytokines by splenic tissue and splenic macrophages between the cirrhosis and control groups was compared with cytokine arrays. Furthermore, splenic macrophages were cultured and stimulated with LPS, after which tumor necrosis factor (TNF)-alpha and interleukin (IL)-12 levels in the supernatant were determined.

RESULTS

In cirrhotic patients, serum LPS levels increased significantly. Interferon-gamma, TNF-beta, and transforming growth factor-beta upregulated, whereas IL-4 and IL-13 levels did not change in splenic tissue. TNF-alpha upregulated significantly, whereas IL-4 and IL-5 levels had no significant changes in splenic macrophages. The IL-12 levels in culture media of splenic macrophages from cirrhotic patients were significantly lower than in controls after LPS stimulation.

CONCLUSION

Splenic macrophages may be activated via incomplete M1 activation in cirrhotic patients with hypersplenism and HBV infection, and the immune function of splenic macrophages is impaired.

Liver transplantation: Yesterday, today and tomorrow

With the advances in technical skills, management of postoperative complications and improvements in immunosuppressive drugs, liver transplantation is the standard treatment for many patients with chronic liver disease. Today, shortage of donor organs seems to be the major limiting factor for the application of liver transplantation. This review focuses on five issues that are challenging to clinical practice of liver transplantation and relevant to gastroenterologists. These include living donor liver transplantation, recurrent viral hepatitis, non-heart-beating donors, hepatocellular carcinoma, and ABO incompatible liver transplantation. Living donor and non-heart beating donor transplantations were initiated as a solution to increase the donor organ pool and it is expected that there will be an increase in the number of these donors. Recurrent hepatitis C and hepatocellular carcinoma following liver transplantation are among major problems and ongoing research in these diseases may lead to better outcomes in these recipients.

The case for combination antiviral therapy for chronic hepatitis B virus infection

The treatment of hepatitis B virus (HBV) infection has been revolutionised in the past decade by the increased availability of effective antiviral agents. Many studies have shown the benefits of single agent therapy, but there is an alarming and rising rate of viral resistance, and clear evidence that viruses that harbour resistant mutations can cause liver disease and death. Current national guidelines for the treatment of HBV recommend a programme that starts with monotherapy, followed by sequential monotherapy or add-on therapy for those infections in which mutations have arisen. Very few studies starting with combination therapy have been undertaken, so there is little evidence of the clinical benefit of this approach to treatment. The studies that have been done have been short term and have concentrated on clinical parameters rather than virological resistance, which is likely to be the key determinant in the longer term. We argue that we should not wait for the evidence to use combination therapy for the treatment of HBV, since such trials may never be done and it would take several years for a benefit to become apparent. In the meantime, multidrug-resistant strains continue to hinder HBV control.

Screening of human antibody Fab fragment against HBsAg and the construction of its dsFv form

The objective of this study was to pursue the techniques involving the screening of the human antibody Fab fragment against hepatitis B virus surface antigen (HBsAg) and the construction of its disulfide-stabilized Fv fragment (dsFv). The phage antibody Fab fragments against HBsAg were screened from the human combinatorial immunoglobulin library. Sequence analysis revealed that its heavy chain gene was complete, but the light chain gene was lost. To improve the affinity of the antibody by chain shuffling, a human antibody light chain gene repertoire was generated by reverse transcriptase-polymerase chain reaction (RT-PCR) from the human peripheral blood lymphocytes. A phage antibody sub-library was then constructed by inserting the light chain gene repertoire into the phagmid that contained the Fd gene. Five clones with appreciably higher absorbance than that of the original clones were obtained, which indicated that the affinity of the light chain-shuffled phage antibodies was improved. Then, the mutated genes of dsFv against HBsAg were constructed by using PCR-based point mutagenesis method. Purified V_H and V_L proteins were folded into a 25-kDa protein, designated as anti-HBsAg dsFv. ELISA and competition ELISA revealed that the dsFv maintained the specificity of the Fab by binding to HBsAg, even through with a lower binding activity. These results have facilitated the undertaking of further functional analyses of the constructed dsFv, and may therefore provide an improved technique for the production and application of dsFvs against HBsAg.

Current concepts in the evaluation of patients for liver transplantation

Candidates for liver transplantation undergo a thorough medical, surgical, psychosocial and financial evaluation prior to listing for transplantation. Prioritization for allocating livers is based upon the model for end-stage liver disease score and waiting-time mortality with the fundamental concept of giving organs to the sickest first. In the upcoming years the allocation system may be modified to include other factors associated with mortality, such as serum sodium, and may incorporate both pre- and post-transplant mortality. Strategies to expand the donor pool include utilizing livers from donors after cardiac death, split liver transplantation and living donor liver transplantation. Future challenges for liver transplantation will include the obesity epidemic and the prevention and treatment of recurrent disease, particularly hepatitis C.