New hypothesis emerges to explain mysterious hepatitis cases in kids
Two viruses and a genetic pre-disposition linked to the puzzling
condition in preliminary data.
Researchers in the United Kingdom have come up with the most detailed,
complex hypothesis yet to explain the burst of mysterious cases of
liver inflammation--aka hepatitis--in young children, which has
troubled medical experts worldwide for several months.
...
...
Combination of factors
But a common feature among the cases has been an infection with an
adenovirus. The extremely common childhood viruses have shown up in
many cases. As such, many hypotheses have involved adenoviruses, but
this, too, is puzzling, because adenoviruses are not known to cause
hepatitis in previously healthy children.
In two new reports, UK researchers offer a fresh hypothesis that may
be the clearest but most complex explanation. Their data suggests that
the cases may arise from a co-infection of two different viruses--one
of which could be an adenovirus and the other a hitchhiking virus--in
children who also happen to have a specific genetic predisposition to hepatitis.
In one of the new studies, looking at nine early cases in Scotland,
researchers found that all nine children were infected with
adeno-associated virus 2 (AAV2). This is a small, non-enveloped DNA
virus in the Dependoparvovirus genus. It can only replicate in the
presence of another virus, often an adenovirus but also some
herpesviruses. As such, it tends to travel with adenovirus infections,
which spiked in Scotland when the puzzling hepatitis cases arose.
Most striking, while all nine of the hepatitis cluster cases were
positive for AAV2, the virus was completely absent in three separate
control groups. It was found in zero of 13 age-matched healthy control children; zero of 12 children who had an adenovirus infection but
normal liver function; and zero of 33 children hospitalized with
hepatitis for other reasons.
This finding was backed up in a separate study led by researchers in
London, which looked at 26 unexplained hepatitis cases with 136
controls. It also found AAV2 in many of the hepatitis cases, but in
very few of the control cases.
Predisposition
The study of the nine cases in Scotland went a step further by
examining the children's genetics. The researchers noted that eight of
the nine children (89 percent) had a gene variant for a human
leukocyte antigen called HLA-DRB1*04:01. But this gene variant is only
found in about 16 percent of Scottish blood donors, well below the
frequency found in the hepatitis cases. Moreover, HLA-DRB1*04:01 is
already known to be linked to autoimmune hepatitis and some rheumatoid arthritis cases.
...
...
Of course, this is just a hypothesis for now--and one mainly based on
only nine cases in a study that has yet to be peer-reviewed.
https://arstechnica.com/science/2022/07/new-hypothesis-emerges-to-explain-mysterious-hepatitis-cases-in-kids/
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)
