From: here@is.invalid   
      
   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-t   
   -explain-mysterious-hepatitis-cases-in-kids/   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)