Hairy Cell Leukemia

So, first off, I’m not a doctor. I think everything here is correct, but please verify with peer reviewed journal articles and/or real doctors, preferably experts in HCL. Back in June, I learned that I had Hairy Cell Leukemia. (HCL) It’s a pretty rare kind of cancer – one estimate I read said there were about 6000 cases in the US, and 600-800 diagnoses a year. As I’ve been dealing with the disease, and learning more about it as I’ve gone through treatment, there’s one big issue that keeps rubbing me the wrong way – there’s precious little information out on the internet about this, and what there is is scattered all over the place. I’m making this post as my small attempt at an all-in-one, narrative guide for folks who have the disease or people who know or care for someone who does. Most of this information can be found at other resources like the Hairy Cell Leukemia Foundation site, and the Hairy Cell Leukemia Support Group on Facebook. I’ve added my own experiences and some of the experiences I’ve heard from others to fill in some of the gaps, or to put the important info all in one place. This is currently a work in progress. more to come.

At a high level, HCL is a disease where B cells, a type of white blood cell, mutate in a specific way, and then are produced at a rapid rate. This ends up causing some problems with the balance of cells in the blood, which is how it’s usually discovered. HCL happens mostly in middle-aged or older people and is slightly more likely in men than women. HCL is often jokingly referred to as “the best cancer to get” because it is relatively easy to treat today. It is worth noting though, that while it can usually be put in remission, there is no cure, and if you have it, you always will. Immediate risks from the disease include the possibility of a ruptured spleen, and risk of bleeding out due to reduced ability of blood to clot. The cause of HCL is unknown, though there has been some speculation (and successful lawsuits) that agricultural chemicals may be a factor.


Where are you in the journey? It seems like information on this topic is easy to organize chronologically in the following phases: Diagnosis, Watch and Wait, Treatment, and maybe Remission.


Diagnosis

The outward signs of HCL are pretty run-of-the-mill – fatigue, bruising easily, enlarged and/or painful spleen, (splenomegaly – generally observed on the left side of the torso around the bottom-front of the rib cage) and sometimes enlarged liver.. The way most people find out they have it is in a routine CBC (complete blood count) before a surgery or other medical procedure. In my case, I was feeling more fatigued than usual over a span of several weeks, and was having other blood work done and asked for a CBC just to see what was going on. Here are a list of tests you’re likely to encounter. More details on each below..

  • Complete Blood Count (CBC)
  • Hematopath
  • Flow Cytometry
  • Diagnostic Imaging (ultrasound/CT scan/PET scan)
  • Bone Marrow Biopsy (BMB)
  • BRAF genetic test

The details of a CBC for someone with HCL can look many different ways. In my case, the only things that were outside of tolerances were that my platelets were about 50% of what they should have been, (thrombocytopenia) and that my Absolute Neutrophils (a type of While Blood Cell) were lower than the standard range. (called neutropenia – this means that you are more susceptible to infection) The CBC may additionally show low Red Blood Cell Count, or other low White Cell counts. These issues alone don’t indicate HCL, they just tell us that something is up and we need to look deeper.

Another thing that may be done at the same time or after the CBC is a Hematopath, or a more manual look at your blood including a pathology review. This is where a Pathologist makes slides of the blood and looks at them to do manual counts and/or visually observe the bloods contents. Regular CBC’s often include automatic counts done by machine. For me, this is the point were it became likely I had HCL – the Pathologist observed the “hairy” protrusions on the B Cells. Generally, doctors want to do more tests before diagnosing, but I don’t think there are any other diseases that manifest with hairy B cells. That said, you CAN have multiple cancers at once, and there are all manner of unknown or lesser known variations on all of them, (including HCL) so it’s best to be very thorough during diagnosis to ensure that you get the right treatment.

A Hairy Cell – Galani KS, Subramanian P G, Gadage VS, Rahman K, Ashok Kumar M S, Shinde S, Mahadik S, Ansari R, Sengar M, Menon H, Nair R, Gujral S. Clinico-pathological profile of Hairy cell leukemia: Critical insights gained at a tertiary care cancer hospital. Indian J Pathol Microbiol 2012;55:61-5

Yet another test that happens at this point or soon after is Flow Cytometry. It’s another blood test that can get more details about individual cells. In this case we are looking at those B Cells. This allows us to do something called Immunophenotyping. Basically, we’re looking at all of the antigen markers and other characteristics of the cell to see what it is like, and then comparing all those characteristics to cells with diseases we know. In some ways, you could think of it as looking at the “fingerprint” of the cell and matching it to diseases with the same fingerprint. This is how we find out exactly what type of cancer it is and if it’s a variant of that type or not. There are several different documented “fingerprints” that align with HCL that doctors might look for. [What does the support group say we are looking for?] link article on FCI.

But wait, there are a couple more common tests.. First, some diagnostic imaging. This comes in many forms, seemingly depending on your Oncologist and the facility where you’re getting care. It seems like there are two reasons for this. One is to get a better estimate of how large your spleen/liver might be. The other is just to see if there are any other “interesting” things going on in your body. My doctor started by saying that we would do something like a sonogram, though once he felt how big my spleen was, jumped immediately to calling for a CT scan with contrast dye. Some folks on the support group got a PET scan instead. In my case, with the CT, we got a visually calculated volume for my spleen.. it was about 2500ml, which appears to be about 2.5 times larger than an average person of my age/size/gender. There was nothing else that looked like cancer, but we did see that I had two kidney stones waiting in the wings, as well as a redundant colon, and a slight hiatal hernia. None of which were really of any immediate consequence. My second opinion doctor, who has been researching and treating HCL for a very long time, used an interesting older method of gauging the size of my spleen by listening with a stethoscope and tapping on my chest with a pen.

Then a bone marrow biopsy, often referred to as BMB. B cells are produced in the bone marrow, so I guess there’s an expectation that the count/percentage of HCL B cells would be best measured there. There are probably other elements of the bone marrow that tell us useful things, but I’ve not seen any of this mentioned, and it seems like most of the other test’s details get us where we need to go with diagnosis. This procedure sounds a little scary, and the way it is conducted can vary a lot, again depending on who your doctor is and what their facility is like. For myself and many other patients, this happens under twilight sedation, (in my case Versed) you’re awake, but a bit loopy, as well as some local anesthesia; in my case, lidocaine injection. Think novocaine at the Dentist’s. I’ve heard that some medical facilities do this without any kind of anesthesia, and it sounds terrible. Probably worth asking about. Another couple things worth asking about are if they will be using any kind of imaging to make sure they use an appropriate spot, as well as asking if someone from hematology will be on hand to validate that the sample they get is sufficient. . If you get the good drugs, the whole thing isn’t bad, but I don’t think anyone would want a second drilling or a return trip after you’ve gone home. In my case, both these things were already covered, and it was good to hear it confirmed when I asked.

As for the process, it was all really fast for me. My actual procedure was only 11 minutes, though I was in the hospital waiting for it for about 6 hours. It went like this: I hung out in a waiting/recovery ward for a long time where they attached vital monitors and IV to me, took some blood, and a doctor came and explained the procedure. Then when it was time, they rolled my bed to a medical imaging equipped room and put me face down on the imaging bed/table. They got my sedation going, then did the Lidocaine with several injections. It stung a little at first, but not bad. Then they imaged me (I don’t know if it was a radiograph or a ct scan) to find an appropriate spot on my pelvis. It was on the Iliac crest, but not at all where I thought that referred to – it ended up being on the back of me, an inch or two from my spine. For me, the sample was taken with an actual drill, albeit a cute little plastic one, which still sounded scary, but ended up not being a big deal. the bit/needle used is 11ga, which was significantly smaller than what I’d been imagining. As they were finishing up, I had a bit of vasovagal response – they noticed my blood pressure dropping, so one of the technicians got me talking, which is a common help for this kind of reaction. Then they bandaged me up, and wheeled me back to recovery to let the sedation wear off. In an hour we were headed back home. I was given 3 different slightly conflicting aftercare instructions.. I basically left the bandage on for a week and did sponge baths. I think you could get away with showering, but you don’t want to sit in a bath because it would make it easy for bacteria to get in. Healing was uneventful. I can feel a little bump there now.

and often run at the same time as the BMB or Flow Cytometry is the BRAF test. This is a genetic test of the Hairy B cells to see if they have the BRAF V600-E mutation. BRAF is a mixed bag.. It’s really important in diagnosing whether you have “classic” HCL or HCLv, a variant that it turns out has not a lot in common with HCL, other than having hairy cells. It also has to be treated differently, and that’s why getting a correct diagnosis is really important. Almost all people with HCL who are BRAF positive have the “classic” HCL, which is easier to treat, so you generally want to be positive.. At the same time, if you are BRAF positive, you are predisposed to other cancers.

The actual diagnosis…

So I mentioned immunophenotyping earlier, but didn’t mention what parts of the results are interesting or what we might be looking for. The HCL carrying B cells have something called antigens. The flow cytometry allows us to test the B cells to see if they are positive or negative for certain antigens we’re interested in. The phenotype is a collection of antigen positivity that matches a known disease. For HCL, the cells are usually positive for CD19 and CD20, CD25, and CD103. There are other markers that may or may not be common. Lots of studies out there with different approaches. I think these markers are enough to rule out other lymphoproliferative diseases.

So once other diseases can be ruled out, it’s important to find out if the HCL is the “classic” or “variant” (also known as HCLv) type. One easy sign is that folks who are BRAF positive almost always have HCL classic. For more specific verification, the phenotype for HCLv is a little different. HCLv has a phenotype too, but I think the pragmatic view is that HCLv lacks a full expression of CD25.

There are some other more rare variants, but I wont claim to know anything about them. I think this is one of the reasons that it’s important to connect with the NIH and get them samples of your blood. They know the larger picture and can recommend treatments.

It’s important to figure out exactly what disease and type you have because the treatments can be different. For example, HCLv treatment doesn’t go well with just Cladrabine, it’s much more successful in combination with other treatments. More on that later.

In my personal experience, this all wasn’t exactly as easy as it maybe sounds above. I am positive for CD19, CD20, CD22, CD11c, CD103, CD25 (subset), CD23, with CD123 (dim/partial), and CD10 and CD5 negative. The subset and dim results confused me, and no doctors were able to explain to me exactly what to make of it. Maybe one view is that “subset” is enough to consider CD25 not a “full” expression, and full expressing is requred for the phenotype? My dim CD123 was remarked as unusual by the hemotologist; usually a dim result here fits more with HCLv. This hasn’t seemed to alert any of the HCL experts, but I still don’t exactly know what it means. Here’s hoping it really is just “classic” and not some sneaky variant that’s resistant to treatment.


Watch and wait
Sometimes the symptoms aren’t bad enough to start treatment, which can be pretty health impacting itself. In this case folks usually have their CBC checked on a cadence, watching for things to get bad enough to start treatment.


Treatment
I’ve done chemotherapy with Cladrabine, and have started an off-label monoclonal antibody therapy called Ofatumumab after having a reaction to Rituxan.. More detail to come on common treatments, side effects, and stuff you might want to do in preparation or going through these treatments..


https://ascopost.com/news/march-2020/first-line-cladribine-with-concurrent-or-delayed-rituximab-for-hairy-cell-leukemia/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7448588/

https://www.nature.com/articles/s41598-021-82841-w

https://ashpublications.org/blood/article/118/21/4622/130529/Combination-Therapy-with-Cladribine-Vorinostat-and

https://n.neurology.org/content/88/16_Supplement/S24.003

https://link.springer.com/article/10.1007/s00277-021-04559-z

https://pubmed.ncbi.nlm.nih.gov/7820054/

https://www.nature.com/articles/s41573-020-00092-2

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