ABC, it's as easy as EBV.

Betcha got that stuck in your head now. Or not and I am just easily amused. A while back I talked about a patient I cared for with pancytopenia. A seemingly otherwise healthy young man, with low everything and negative tests (when he was on my floor) for malignancy and infection. As I so famously said back then; what the hell? 

Let’s quick recap. The bone marrow is the origin point for many of the cells that make up our blood, some end up in other tissues to mature into their specific role in the body. Screwing with one of those steps (simplified) can really throw a spammer in the works. I’ve made the analogy before about it being easier to intervene in an earlier stage than a later stage. Think a construction site vs skyscraper, 6 weeks pregnant vs 30 weeks, etc…

EBV is an outrageously huge subject so I’m just skimming on part of the surface. First, if you want a much better idea of what this is, listen to the EBV episode of This Podcast will Kill. YouThat’s Epstein-Barr Virus FYSA. EBV is a pretty ubiquitous herpesvirus that an estimated 90% of the population has contracted. I say contracted not gotten sick because the virus can remain latent for a long time. So can we even know if it is cleared? Let me know. 

Many of us have probably heard of mono or mononucleosis, sometimes called kissing disease. Ewww kissing. Gross. It is spread by saliva from infected individuals and generally resides in B cells and epithelial cells (the cells that line the surface of our bodies, though in this case generally respiratory and oral surfaces). The cool or terrifying thing about this is that the B cells, when highjacked, incorporate the EBV DNA and form memory B cells. But this highjacker doesn’t always make itself known. EBV can remain latent waiting for the chance to start the genetic machinery to replicate. Sneaky bastards. Additionally, EBV virons from epithelial infection have affinity towards B sells and vice versa. This means the virus will always end up in the salivary glands, where it can make the jump to new hosts. 

When the host immune system takes a three week vacation to the Amalfi Coast, then the EBV infected cells begin to replicate and then may cause active infection. At least until the immune system comes back and tries to take a bat to EBV and send it back into hiding. Fun fact, it is thought that when latently infected B cells activate to do their job and attack unrelated infections, that might be the trigger to start EBV replication. Ok. I could talk about getting sick but what does this have to do with pancytopenia? 

EBV has been linked to several diseases and cancers, and is thought to cause them through chromosomal damage. This damage is suspected to cause disruption of genera that control how often cells divide, leading to more cells and more damage. This can happen in the lymph nodes causing lymphomas. And when this happens to bone marrow cells, we get cancers called leukemias. Though, these usually present with more symptoms than this patient had but these could also be present asymptomatically. All this to say, could it be undiscovered malignancy? It is common for many cancers, especially leukemias, to cause different blood dysfunctions. The body is amazing and resilient but also can be thrown out of whack by hundreds of factors.

We have made unbelievable progress in understanding how the body works and how it responds to disease and non pathological environmental factors. Even that hasn’t given us the ability to make perfect diagnoses. This mystery is what draws many of us, including me, to healthcare. To provide compassionate care while striving to understand the human body. I probably will never know what happened (I’m still going to post on my thoughts) but I damn sure can take care of patients like the subject here. Don’t forget about the human part of the problem. 

I hope you learned at least one thing here. As I hope to take my boards this week I don’t know if I’ll post till after that. But please go and check out the Occasionally Preposterous podcast on iTunes or Spotify and share both with anyone you think might enjoy this kinda shenanigan. Love y’all. 

References 

Epstein Barr virus from the NIH National Library of Medicine by Higginbotham and Hoover.

Image of EBV from the NIH National Library of Medicine. 

Leukemia from NIH National Library of Medicine by Chennamadhavuni et al.

Neutropenia from the NIH National Library of Medicine 2022 by Vaillant and Zito. 

Severe neutropenia from the Western Journal of Medicine by Munshi and Montgomery in 2000  



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