Doctors and scientists around the world continue to investigate cases of hepatitis of unknown origin which are multiplying in the world.
Affected patients already number 450, according to a report by the European Center for Disease Prevention and Control (ECDC), nearly 100 more than the 348 reported by the World Health Organization (WHO) in its latest report.
Doctors Petter Brodin and Moshe Arditi published a scientific study yesterday in the prestigious medical journal The Lancetin which they investigated the causes of several of the detected cases of the disease of unknown origin.
“Recently, cases of children with a severe acute form of hepatitis in the UK, Europe, USA, Israel and Japan. Most patients present with gastrointestinal symptoms, then progress to jaundice and, in some cases, acute liver failure. So far, no common environmental exposures have been found, and an infectious agent remains the most plausible cause,” the researchers said.
“The viruses of hepatitis A, B, C, D and E were not found in these patients, but 72% of children with severe acute hepatitis in the UK who were tested for adenovirus had adenovirus detected, and in 18 cases subtyped in the UK, all were identified as adenovirus 41F. This subtype is not uncommon but mainly affects young children and immunocompromised patients. However, to our knowledge, adenovirus 41F has never been reported to cause severe acute hepatitis.”
They then indicated that the SARS-CoV-2 it was identified in 18% of reported cases in the UK and 11% of 97 cases in England with available data who tested positive for SARS-CoV-2 on admission; three other cases had tested positive within 8 weeks of admission.
“Ongoing serological testing is likely to show an increased number of children with severe acute hepatitis and previous or current SARS-CoV-2 infection. 11 of 12 Israeli patients are believed to have had COVID-19 at months, and the majority of reported cases of hepatitis have been in patients too young to be eligible for COVID-19 vaccines. SARS-CoV-2 infection may result in the formation of a viral reservoir,” they explained.
And they added: “The viral persistence of SARS-CoV-2 in the gastrointestinal tract can lead to the repeated release of viral proteins through the intestinal epithelium, leading to immune activation. Such repeated immune activation could be mediated by a superantigen motif in the SARS-CoV-2 spike protein that resembles staphylococcal enterotoxin B, triggering broad and non-specific T cell activation by superantigens has been proposed. as a causative mechanism of multisystem inflammatory syndrome in children,”
The authors noted that there have been reports of hepatitis in children with multisystem inflammatory syndrome, but co-infection with other viruses has not been studied. “We hypothesized that recently reported cases of severe acute hepatitis in children may be a consequence of adenovirus infection with intestinal trophism in children previously infected with SARS-CoV-2 and carrying viral reservoirs “, they noted.
Experts have pointed out that in mice, adenovirus infection sensitizes to subsequent toxic shock mediated by staphylococcal enterotoxin B, leading to liver failure and death. “This finding was explained by an adenovirus-induced type 1 immune bias, which, following subsequent administration of staphylococcal enterotoxin B, led to excessive production of IFN-γ and apoptosis mediated by IFN-γ from hepatocytes,” they noted.
“Translated to the current situation, we suggest studying the persistence of SARS-CoV-2 in feces, hijacking of T cell receptors and upregulation of IFN-γ in children with hepatitis acute, as this could provide evidence for a SARS-CoV-2 superantigen mechanism in an adenovirus-41F-sensitized host.If evidence of superantigen-mediated immune activation is found, immunomodulatory therapies should be considered in children with severe acute hepatitis,” the researchers concluded.