CD4+ Cytotoxic T Cells Involved in the Development of EBV-Associated Diseases, 2022, Ruiz-Pablos

I would like to share with you my latest review article. The Epstein-Barr virus (EBV) has long been known to be behind the development of autoimmune diseases, cancer and is even suspected to be behind the development of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Long COVID. But it is still unclear what pathways it uses.

In this review I describe how the possession of certain ancestral HLA-II alleles (a system used by our immune system to recognize which proteins are foreign, such as pathogens, and which are not) makes the individual genetically weak to control EBV latent cells, thus developing different diseases. EBV infects B cells through a protein on its surface called gp42, which allows it to bind to HLA-II molecules on the B cell surface. If the individual possesses ancestral HLA-II alleles susceptible to EBV, it will cause that after the infection of B cells and the establishment of the latent form, the antigen presentation of these cells will be altered, since gp42 would remain bound to HLA-II molecules interfering in the presentation of antigens to T lymphocytes (necessary to eliminate infected cells), and in the activation of these. This protects the cell from being recognized by CD4+ T lymphocytes and thus surviving, since B cells are one of the main cells that regulate our immune system. But the consequence of possessing these weak alleles against EBV is the development of a type of immunodeficiency, by preventing the activation of CD4 T cells by the interaction of gp42.

Another advantage of infecting B cells is that they have the ability to form ectopic lymphoid aggregates in any tissue. This, under normal conditions, is useful to fight infections in the affected tissue better and faster, since these cells are responsible (among others) for presenting antigens to CD4 T cells and generating antibodies. But EBV takes advantage of this pathway to survive, since any inflammatory process (due to infection or for any other reason) occurring in any tissue recruits both healthy B cells and B cells with latency to the inflamed tissue. In this inflamed tissue they form ectopic lymphoid aggregates similar to germinal centers (central factories for the generation of high affinity immunoglobulins against pathogens). Finally, these ectopic lymphoid aggregates become reservoirs of EBV latent cells generating a chronic infection with viral reactivations in these tissues. Moreover, being B cells, they have the capacity to present antigens. Therefore, those B cells and epithelial cells modified by EBV could present antigens from that tissue as foreign proteins and thus cause the development of autoimmune diseases. This occurs by presenting self-antigens on HLA-II molecules altered by gp42. Thus, depending on the tissue infiltrated by these cells with EBV latency, one type of autoimmune disease or another will be generated. For example, if they infiltrate the thyroid they could generate autoimmune thyroiditis, in the intestinal mucosa they could generate celiac disease, if they infiltrate the pancreatic islets they would generate type 1 diabetes, if they do so in the central nervous system they would generate multiple sclerosis, in the exocrine glands they would generate Sjögren's syndrome, in the thymus they would generate myasthenia gravis, in the synovial joints they would generate rheumatoid arthritis and so on with the rest of the tissues. In addition, if these latent cells are not controlled, cancer may develop after a few years. For this reason, patients with autoimmune diseases have a higher risk of developing them.


This model not only explains the development of the diseases described here, but also others, such as EBV-associated gastric carcinoma, in which the formation of these ectopic lymphoid structures in the gastric mucosa in response to Helicobacter pylori infection or another inflammatory process causes the infiltration of B cells with EBV latency in the lymphoid aggregates, and the subsequent infection of epithelial cells when expressing MHC-II, due to an increase in IFN-γ. Finally, the immune evasion microenvironment generated by these EBV-transformed cells and the clonal growth of EBV-latent epithelial cells would lead to the development of the disease. This model could even explain the involvement of EBV in the development of chronic fatigue syndrome or myalgic encephalomyelitis and Long COVID. Both diseases present similar EBV reactivations and chronic symptoms, which could suggest a common EBV immunopathology. In the case of Long COVID, inflammation caused by SARS-CoV2 infection of tissues would recruit B cells with EBV latency, where ectopic lymphoid aggregates could form and lead to viral reactivations. Likewise, it could also help us understand why EBV-associated autoimmune diseases, Long COVID and chronic fatigue syndrome/myalgic encephalomyelitis are more common in women. Estrogens, by increasing B-cell survival, would allow a greater permanence of these ectopic lymphoid aggregates with EBV latency in the inflamed tissues of patients with "ancestral" HLA-II alleles and, therefore, a chronification of symptoms.


Attached is the link to the manuscript with some treatment proposals:

https://www.mdpi.com/2076-0817/11/8/831


You can also read this other article to understand how EBV can develop Chronic Fatigue Syndrome or Myalgic Encephalomyelitis:

https://www.frontiersin.org/articles/10.3389/fimmu.2021.656797/full

You can enter in this twitter thread where I am answering your questions:
https://twitter.com/i/web/status/1551975198945157120

Best regards,
Manuel.

 

Here's a Twitter thread on this:

 

Hello Manuel and welcome here.
Thank you for sharing your paper and congratulation on this publication.

What jumped to my eye by quickly reviewing what you wrote is the last paragraph in relation to my personal experience in getting EBV. I actually contracted EBV from work-related saliva exposure from a gastric cancer patients as I was starting his IV. The EBV infection was documented via lab and I have been sick with ME for 13+ years. Within 5 months of this infection I developed a large ovarian cyst (8 cm-benign) and a necrotic gallbladder.

My question to you is: 1) are you planning to do a follow up study in relation to ME and EBV, or Long-Covid and EBV? What direction would it take (if it's not confidential)?
2) Would testing the HLA alleles that you mentioned been done for ME and would these be covered by the UK genomic study (@Andy )?

I will now go on twitter to check out your thread.
Best regards.

 

@Manuel, thank you for posting. I have insufficient cognitive functioning today to assimilate this, but will return hopefully tomorrow.

Being one of the many whose ME onset, some thirty years ago, was associated with an acute EBV infection, I am already primed to suspect that EBV is implicated in the genesis of ME.

 

Do you have a hypothesis as to which tissues would potentially get infiltrated in the case of ME and LC to generate our particular phenotype/s (maybe you explain this in the paper but I'm not up to reading it to find out)?

 

Thank you for sharing this @Manuel , it sounds very interesting. I am not a scientist and don't have the understanding that some people on this forum have. However, bits of your paper stand out to me on a personal level. I have a close family member who has had Burkitt's lymphoma and another relative with non-Hodgekin's lymphoma (and I have ME). I have two questions:

1) Do you think the DecodeME GWAS trial might tell us whether these haplotypes are present in pwME?

2) Do you think your hypothesis might describe a sub-group of pwME, or do you think this is relevant to ALL pwME?

 

My blog on the HLA research:
https://mecfsresearchreview.me/2020...that-immune-system-problems-can-cause-me-cfs/
(sorry, don't have the capacity to follow this thread properly but post in case this is relevant.)

 

Wasn't there something with HLA Alleles and ME/CFS patients responding to cyclophosphamide?

 

Yes.

“Patients positive for HLA-DQB1*03:03 and/or HLA-C*07:04 (n = 12) had significantly higher response rate compared to patients negative for these alleles (n = 28), 83 vs. 43%, respectively. “

 

As soon as I can I will respond to your comments. In the meantime, here are some of the answers I have posted on Twitter:

“After so many years of work and as a post Epstein-Barr virus infection ME/CFS sufferer it makes me really happy that they have put our article on the cover of the August issue of Pathogens journal:
https://www.mdpi.com/2076-0817/11/8

Until recently nobody talked about post-viral syndromes (actually they should be called chronic infectious syndromes) and they left all of us patients isolated both at a health and social level.

Unfortunately it took another virus like SARSCoV2 to show us how viruses are capable of developing chronic diseases like Long COVID. It is curious that for bacterial infections we use antibiotics but for viral infections we leave it to our immune system to manage to control it. This must change. We must prevent with antiviral treatments to prevent the development of chronic diseases such as Long COVID, ME/CFS, autoimmune diseases and even cancer. It is absurd to think that everyone's immune system can resolve most viral infections. Patients who develop diseases associated with these viruses were previously completely healthy. Having one or another type of MHC-II allele can make you weaker or more resistant to certain viruses. In the case of herpesviruses, it is not the viral particles that are the problem, but the latent cells that cause the immune disruption. The Epstein-Barr virus (EBV) is one of the oldest viruses with which humans have coexisted, even since we were apes. Living with this virus has led to the evolution of its evasion mechanisms and also of our resistance mechanisms (MHC-II alleles).

In the case of EBV, the patient only needs to have one of the "ancestral" alleles (the oldest) of the MHC-II weak against EBV, since one of the main reasons why this virus is related to the MHC-II alleles is because it infects cells through the interaction of its viral protein gp42 with the cell's MHC-II. In this way it fuses its membrane with that of the cell, forming a new gp42-MHC-II complex that alters antigenic presentation to CD4 T cells, since MHC-II is essential for the immune system to know what is foreign and what is not. By decreasing this antigen presentation to CD4 T cells, an acquired immunodeficiency develops that allows any inflammatory stimulus (other infection) in any tissue to lead to the formation of EBV-infected ectopic lymphoid aggregates. This, together with the altered immunosurveillance caused by the evasion mechanisms of these cells with EBV latency (increased Th2 and Treg), would lead to increased proliferation of these cells, which would increase the risk of neoplastic transformation or autoimmune disease in these tissues.

In the case of Long COVID two things can happen. That patients have other "weak" HLA alleles against that virus or that they are the same weak alleles against EBV, allowing SarsCov2 infection to cause recruitment of B cells with EBV latency and form these lymphoid aggregates. In other words, EBV is an opportunistic virus that takes advantage of the infection of other pathogens to settle in different tissues.

These tissues finally end up with chronic inflammation by activating receptors (TLRs) that continuously detect viral genetic material, causing an increase in the inflammatory and innate response but without the adaptive response being able to control the infection completely due to the decrease in the activation of CD4 T cells. This acquired immunodeficiency also causes reactivation of other latent pathogens such as other herpesviruses and Parvovirus B19, adding more problems and more inflammation. That is why it is common to have viral reactivations in all EBV-associated diseases.

Based on the hypothesis that the problem is EBV latency cells, there are few effective treatments. If you restore cortisol levels with corticosteroids you can further immunosuppress the Th1 response and therefore further proliferation of these latency cells. If you give antivirals against EBV you prevent viral replication but you do not eliminate the latent cells. If you only give antivirals against SarsCoV 2 you do not eliminate the ectopic lymphoid aggregates with EBV latency that have formed and therefore the problem will continue. And if you try to reduce the proinflammatory cytokines with some immunomodulatory therapy, the immunodeficiency caused by the gp42/MHC-II interaction is not eliminated, so the CD4 T cells will not recognize well the cells with EBV latency I. The treatment that would be useful would be a combination of antivirals and some treatment that would make the cells with latency move to the lytic phase or move to another type of latency that is recognized by the T cells. “

“DR2-DQ6, DR3-DQ2 and DR4-DQ8 are among the oldest haplotypes in existence. These haplotypes have survived over time because they are able to recognize a greater number of antigens compared to other haplotypes, allowing them to better eliminate some pathogens. For example, individuals carrying the HLA-DR4 allele were significantly associated with greater clearance of hepatitis B virus infection. The presence of HLA-DRB1*0401 and DRB1*1501 has been associated with greater clearance of hepatitis C virus infection. And so on with other pathogens. This means that these haplotypes have survived over time and have been inherited from population to population to this day. But they have a disadvantage and that is EBV.

Since EBV is the only member of the genus Lymphocryptovirus adapted to humans, transferred to a hominid ancestor millions of years ago, it could be hypothesized that EBV immune evasion mechanisms have evolved to evade these haplotypes. Furthermore, these haplotypes have the ability to generate strong Th1 responses, releasing IFN-γ. This provides a great advantage against many pathogens but not EBV. Since IFN-γ increases MHC-II expression in cells that previously did not express it, allowing the virus to infect even more cells through gp42-MHC-II interaction. This together with the altered antigenic presentation due to gp42, causes an increase in cells with EBV latency I and 0, increasing the evasion mechanisms of these cells (increased T-reg and IL-10) that generate an increased Th2 response and therefore a greater chronification of the infection.

But why is it EBV that generates all these diseases with these resistant haplotypes against other pathogens? Because not all individuals carrying these haplotypes have developed these diseases. Only a subset have developed them, indicating that there is an environmental factor (EBV infection) that is the origin of these diseases. Especially because it is closely related to the alleles of the beta domain of HLA-II, when infecting through this pathway.

Co-infections of other pathogens in individuals carrying these haplotypes and having EBV also play a role. Any tissue infected by another pathogen increases the inflammation of this tissue by recruiting cells. with EBV latency and forming ectopic lymphoid aggregates with EBV. Autoimmune diseases may develop in these tissues. This supports the fact that the likelihood of developing Long COVID increases the more reinfections they have had with SARS-CoV2.

So treatment against these EBV latency cells would help eliminate all EBV-associated diseases.”