Epstein-Barr Virus and PSC
PSC Research Explained
PSC Research Summaries and Updates
PSC and Epstein-Barr Virus
New research published in the leading journal Nature Medicine has established strong evidence of a link between Epstein-Barr virus (EBV) infection and PSC.
What was the aim of the research?
The researchers wanted to explore whether there could be a link between EBV infection and development of PSC. EBV has already been linked to several other diseases with an autoimmune component.
What is Epstein-Barr virus?
90 to 95% of us have been infected with this virus, mostly in early childhood without much in the way of symptoms. Later infection, usually in our teens, can result in glandular fever (also known as infectious mononucleosis). After initial infection the virus often remains in our bodies hiding away (dormant) in our B cells which are part of the immune system. In certain situations the virus can reactivate.
What did the scientists study and what did they find?
There were 3 parts to this study:
T cell comparison
They investigated T cells, immune cells that have a wide variety of receptors on their surface, ready to detect and respond to many different infections. The types of receptors on the T cells were compared in 504 people with PSC and 904 healthy people.
In the PSC group, a greater proportion of T cells had receptors that could respond to EBV than in the healthy control group.
B cell comparison
They investigated B cells, immune cells that produce antibodies to fight off infections. Different B cells produce different antibodies. The variety of antibody output of 120 people with PSC was compared with that of 202 healthy people.
An increased antibody response directed toward EBV was found in people with PSC. Also the proportions of the different types of antibodies against the virus in those with PSC was suggestive of reactivated viral infection.
Medical records analysis
They analysed 116 million health records, looking for any relationship between diagnoses of glandular fever and PSC.
They found that individuals diagnosed with glandular fever have a 12 fold increased risk of developing PSC.
What did the researchers conclude?
The evidence from all three parts of this study pointed to a strong association between EBV and PSC.
They suggest that reactivation of the virus from a dormant state is probably involved in the emergence of PSC in an individual.
The scientists cautiously point out that at this stage they cannot definitely say that EBV causes PSC - this would need more research.
Is there anything to be excited about here?
The pattern of the association between EBV and PSC does look rather similar to a link that has already been discovered between EBV and another disease involving autoimmunity, multiple sclerosis (MS).
After lots of research on EBV and MS, scientists are confident that ongoing EBV infection drives the progression of MS in the body. In fact a medical trial is just starting in the UK on MS patients to see whether an experimental vaccine against EBV could help the immune system better deal with the EBV virus. The hope is that vaccination could slow or halt the progression of MS.
The new vaccine has been developed by the drug company Moderna, using the same messenger RNA vaccine technology that they used in their successful COVID vaccine.
Next Steps
If further research on PSC and EBV were to provide good evidence that EBV is definitely driving the development of PSC and its progression, then maybe there will be a place for a similar trial of an EBV vaccine in PSC patients. Watch this space!
Thanks to research volunteer, David Laird, for writing this lay summary.