Reactivación de la hepatitis B asociada a agentes inmunodepresores y a quimioterapia. Historia natural, factores de riesgo y recomendaciones para prevenirla

Therapeutic Exploitation of Viral Interference

Viral interference, originally, referred to a state of temporary immunity, is a state whereby infection with a virus limits replication or production of a second infecting virus. However, replication of a second virus could also be dominant over the first virus. In fact, dominance can alternate between the two viruses. Expression of type I interferon genes is many times upregulated in infected epithelial cells. Since the interferon system can control most, if not all, virus infections in the absence of adaptive immunity, it was proposed that viral induction of a nonspecific localized temporary state of immunity may provide a strategy to control viral infections. Clinical observations also support such a theory, which gave credence to the development of superinfection therapy (SIT). SIT is an innovative therapeutic approach where a non-pathogenic virus is used to infect patients harboring a pathogenic virus. For the functional cure of persistent viral infections and for the development of broad- spectrum antivirals against emerging viruses a paradigm shift was recently proposed. Instead of the virus, the therapy should be directed at the host. Such a host-directed-therapy (HDT) strategy could be the activation of endogenous innate immune response via toll-like receptors (TLRs). Superinfection therapy is such a host-directed-therapy, which has been validated in patients infected with two completely different viruses, the hepatitis B (DNA), and hepatitis C (RNA) viruses. SIT exerts post-infection interference via the constant presence of an attenuated non-pathogenic avian double- stranded (ds) RNA viral vector which boosts the endogenous innate (IFN) response. SIT could, therefore, be developed into a biological platform for a new "one drug, multiple bugs" broad-spectrum antiviral treatment approach.

Consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B virus infection (2020)

Hepatitis B virus (HBV) infection remains a global public health problem. HBV vaccination is the most effective tool to reduce the incidence of HBV disease. Despite there has not been new clinical developments for the treatment of chronic hepatitis B in the last few years, changing epidemiology and current insights on natural history, diagnostic tools and therapy indications make necessary an update of the former version of the consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B infection published in 2012. The current document updates the management of chronic hepatitis B. The treatment of choice is the long-term administration of a nucleos(t)ide analogue with high barrier to resistance (entecavir, tenofovir or tenofovir alafenamide). Pegylated interferon may be an option in patients with non-advanced liver disease, but its applicability is limited due to the low efficacy and poor tolerability. All patients must be monitored for the risk of progression to advanced liver disease and development of hepatocellular carcinoma.

Reactivation of hepatitis B virus infection in patients with hemo-lymphoproliferative diseases, and its prevention

Reactivation of hepatitis B virus (HBV) replication is characterized by increased HBV-DNA serum values of about 1 log or by HBV DNA turning positive if previously undetectable in serum, possibly associated with liver damage and seldom life-threatening. Due to HBV reactivation, hepatitis B surface antigen (HBsAg)-negative/anti-HBc-positive subjects may revert to HBsAg-positive. In patients with hemo-lymphoproliferative disease, the frequency of HBV reactivation depends on the type of lymphoproliferative disorder, the individual's HBV serological status and the potency and duration of immunosuppression. In particular, it occurs in 10%-50% of the HBsAg-positive and in 2%-25% of the HBsAg- negative/anti-HBc-positive, the highest incidences being registered in patients receiving rituximab-based therapy. HBV reactivation can be prevented by accurate screening of patients at risk and by a pharmacological prophylaxis with anti-HBV nucleo(t)sides starting 2-3 wk before the beginning of immunosuppressive treatment and covering the entire period of administration of immunosuppressive drugs and a long subsequent period, the duration of which depends substantially on the degree of immunodepression achieved. Patients with significant HBV replication before immunosuppressive therapy should receive anti-HBV nucleo(t)sides as a long-term (may be life-long) treatment. This review article is mainly directed to doctors engaged every day in the treatment of patients with onco-lymphoproliferative diseases, so that they can broaden their knowledge on HBV infection and on its reactivation induced by the drugs with high immunosuppressive potential that they use in the care of their patients.