Viral infection and genetic variant are associated with cases of hepatitis in children

A complex of factors may be responsible for cases of hepatitis in children that have been baffling doctors in recent months, according to two small new studies.

The studies are based on a few dozen cases and have not yet been reviewed or published in scientific journals. However, they suggest that children who had severe, unexplained cases of hepatitis may have been simultaneously infected with two different viruses, including one known as adeno-associated virus 2 (AAV2), a usually benign virus that requires a “second helper”. The virus is in order to reproduce.

Adenoviruses, previously found in many children with occult hepatitis reported over the past year, are common AAV2 adenoviruses.

The scientists found that many of the children in the study also had a relatively uncommon version of a gene that plays an important role in the immune response.

Together, the findings suggest a possible explanation for the cases of hepatitis: in a small subset of children with this particular genetic variant, double infection with AAV2. The helper virus, often an adenovirus, triggers an abnormal immune response that leads to liver damage.

However, the researchers acknowledged that the studies were based on a small number of children in only one region of the world (the United Kingdom) and that causation had not been proven.

Dr. said. Antonia Ho, senior clinical lecturer at the Center for Virus Research at MRC-University of Glasgow and author of one of the new studies.

But she added: “We felt – because there were so few answers about the causes – that we needed to publish these results so that others could start looking for AAV2. And investigate this in more detail.”

Dr. said. Saul Karpen, a pediatric hepatologist at Emory University and Child Care in Atlanta, who was not involved in the research. “This is not a definitive study,” he said. “Objectively speaking, it could certainly make sense, but there is no complete backing for it.”

Cases of hepatitis in children are extremely rare but can be severe. As of July 8, 1,010 probable cases have been reported from 35 countries, according to the World Health Organization. Five percent of these children required liver transplants, and 2 percent died.

Several early studies found that many children were infected with adenovirus, one of a group of common viruses that cause cold or flu symptoms. New studies suggest that if adenoviruses are implicated in cases of hepatitis, they may only be part of the story.

In one new study, scientists compared nine Scottish children with unexplained hepatitis with 58 children in control groups. The researchers used genetic sequencing to identify any viruses present in the blood, liver and other samples of the children.

The scientists found adeno-associated virus 2 in the blood of all nine infected children and in liver samples from all four of the children who had these samples available. They also found adenovirus in six of the children and herpes common virus in three.

On the other hand, researchers did not detect AAV2 in healthy children, children with adenovirus infection but normal liver function or in children with hepatitis of known causes.

These findings are consistent with those of a second study, led by researchers in London, which examined samples from 28 children with unexplained hepatitis from across the UK. This scientific team also found high levels of AAV2 in the blood and liver of several children. Several also had low levels of adenovirus or herpesvirus in their samples.

The Scottish researchers also found that eight of the nine affected children, or 89 per cent, share a relatively uncommon type of gene that codes for a protein important in the body’s immune response. This particular type is present in only 16% of blood donors in Scotland.

The London team found the same genetic variant in four of the five transplant recipients they evaluated.

“Both studies independently came to remarkably similar results,” Sophia Morphopolo, a computational statistician at the Great Ormond Street Institute of Child Health at University College London and author of the second paper, said in an email.

Although the idea is still preliminary, the scientists said, it is possible that the recent resurgence of the adenovirus after a drop in circulation during the coronavirus pandemic explains why doctors have noticed a sudden rise in these rare cases.

Dr. said. Emma Thompson, an infectious disease doctor at the Center for Virus Research and lead author of the Scottish study.

The researchers said additional, larger studies are still needed, especially with a focus on children in other countries.

Leave a Comment