To Kiss or Not to Kiss? Links between EBV and MS
By Miriam Goodwin
With Covid restrictions becoming looser, some will find themselves in new situations. Do you kiss the stranger across the room, do you share your boba on the first date, do you even share a water bottle with your roommate? Mono, or the Epstein Barr Virus (EBV), is a persistent virus that infects B cells in the lymph nodes, which comes with some pretty hefty side effects, such as fatigue, sore throat, and some very swollen lymph nodes. However, as it turns out, the virus can have worse effects than causing you to miss a week of classes. This chronic illness destroys the myelin sheath- or the protective covering of the nerves in your brain, optic nerves, and spinal cord- causing degradation of the Central Nervous System (CNS). The causes of the disease are unknown and it has no cure
Scientists at Harvard seemed to have found the culprit- Epstein Barr Virus. The hypothesis that MS is caused by EBV was tested amongst a group of more than 10 million young adults on active duty in the US military. It was found that after being infected with Epstein Barr Virus, the risk of developing MS increased 32-fold after seroconversion, or when antibodies show up in the blood.
The study matched two randomly selected individuals without Multiple Sclerosis based on age, sex, race/ethnicity, branch of military service, and dates of blood samples collection who were on active military duty when the case was diagnosed. Within this group, there were 801 MS cases and 1566 controls. To show the relationship between Epstein Barr Virus infection and MS, the amount of neurofilament light chain (sNFL) – not disease-specific to MS, but a sign of degeneration in the brain- is tested in serum.
In individuals who were not infected with EBV but developed MS, it was found that there were no signs of neuroaxonal(axon of the neuron)degeneration before their body developed EBV antibodies, but rather the degeneration came after infection with EBV. This indicates that EBV infection comes not only before symptoms but before the first detectable mechanism of MS via the amount of degeneration levels within the brain.
Researchers found that levels of neurofilament light chain- a marker of brain degeneration- in serum increased only after the body produces antibodies for Mono. Scientists used a similar virus- cytomegalovirus(CMV) – also herpes virus spread by saliva, as a way to account for the environmental, behavioral, or personal characteristics that can cause disease. CMV was the ideal candidate for a negative control as it impacts a similar socio-economic group and has a similar seroconversion rate (time for the body to create antibodies) as EBV. When looking at CMV, it was actually found that the risk for MS decreases when infected with CMV, showing that the virus causes an adverse immune response to EBV. Along with the results, during the preclinical phase, scientists randomly selected 30 MS cases and 30 matched controls with serum shortly before and after MS symptoms began by using VirScan to scan non-EBV antibody responses. The scan found that early phases of MS were not associated with any breakdown of the immune system that would impact sustainability to infection. However, the scan showed a large amount of EBV peptides in both pre and post symptoms presentation of MS, which shows EBV to be the primary known cause of MS. (Fig E. and F.) Further proving that EBV plays a role in the development of MS.
The graphs show the difference between the number of peptides of the virus in the body before and after MS.
In the future researchers hope to further explore the cause of MS, by continuing research on the association between Epstein Barr Virus and MS along with the potential link between MS and having homozygosity for the HLA-DR15 allele, which has shown to increase MS by three percent. By further researching the cause of Multiple Sclerosis potential cures or actions to prevent the disease can be taken. In the meantime, you should think twice about who you are locking lips with.
References
- Bjornevik et all, “Longitudinal Analysis Reveals High Prevalence of Epstein-Barr … – Science.org.” Science.org, 2022, https://www.science.org/doi/10.1126/science.abj8222.