The hepatitis C virus. Image: TCD
Researchers at Trinity College Dublin have solved the mystery of how the hepatitis C virus escapes detection until it’s too late.
Highly infectious and seriously harmful if left untreated, hepatitis C is one of the most elusive viruses around. The virus is typically transmitted through infected blood and, over the past number of decades, has been given to many patients across the world accidentally.
However, even though the hepatitis C virus (HCV) can be deadly, initial infection is rarely accompanied by any obvious symptoms. This means that a person can go undiagnosed for between six and 12 months after infection.
It eventually does appear as ‘jaundice’, where reduced liver function leads to a build-up of toxins, giving skin a yellow colour.
While the majority of HCV infections are now treatable with new medicines, early detection would avoid the development of liver disease as a result of the virus replicating in great numbers in the organ.
To this end, researchers from Trinity College Dublin (TCD) have published findings to The FASEB Journal documenting the discovery of how HCV ‘ghosts’ the immune system and prevents any symptoms from appearing soon after infection.
How it works
Under normal circumstances, our cells communicate with each other using molecules called cytokines, which trigger signalling pathways to increase inflammation and antiviral activity, thereby killing and clearing viral infections.
Given that uncontrolled inflammation would seriously harm the body, several cytokine-signalling pathways are controlled by immune regulators called ‘suppressor of cytokine signalling’ (SOCS) regulators. After a period of time following an initial response, pro-inflammatory cytokine-signalling pathways are shut down by SOCS regulators.
Now, the TCD scientists have found that HCV ghosts our immune response by triggering these SOCS regulators, as the job of a specific part of the virus is to increase a specific molecule in both liver and immune cells.
“This ability shields HCV from our body’s normal, effective, antiviral immune response and creates a perfect environment in which to survive, replicate and infect other cells,” said Nigel Stevenson, who led the research team.
“Many diseases are mediated by increasing the inflammatory response to an inappropriately high level, but in this case it is the lack of adequate inflammation that enables HCV to go undiagnosed, leaving it free to rapidly replicate and infect other cells.”
