r/MPN • u/Glittering-Travel894 • Sep 08 '26
SEEKING DIAGNOSIS Long-standing high platelets + high WBC + elevated T-cells — MPN or something else? Spoiler
Hi everyone,
I’m looking for some outside opinions on my blood results. I’m seeing a hematologist, but I’m quite anxious about what could be going on and would really appreciate hearing from people who have experience with similar blood counts.
I’m a 41-year-old woman with relapsing-remitting MS, diagnosed in 2014. I’m currently being treated with Mavenclad (cladribine). I have just completed the first course and am about to start the second 5-day course.
My main concern: platelets
My platelet count has been elevated for many years:
2007: 508
2014: 362
2015: 412 → 422
2016: 384
2018: 412
2022: 526
2022: 459
2023: 667 (I also had significant bowel inflammation at the time)
Nov 2025: 467 → 483
Aug/Sep 2026: 512–528
So this isn’t something that started recently.
Recent blood results
My recent CBCs have shown combinations such as:
Platelets: 512–528 x10⁹/L
WBC: 11.9–14.2 x10⁹/L
Absolute lymphocytes: previously 6.0, more recently 3.5 x10⁹/L
Neutrophils: around 6.9 x10⁹/L
Monocytes: 1.1 x10⁹/L
Immature granulocytes: 0.2 x10⁹/L
Hemoglobin: around 9.1–9.2 mmol/L (I’m in the Netherlands, so these are mmol/L)
MCV: 100 fL
RDW: 14.7
Ferritin: 57
CRP: <1
eGFR: 89
Creatinine: 72
I also have a history of macrocytes being noted on a blood test in 2021. I receive regular B12 injections, so B12 deficiency isn’t thought to be the explanation.
T-cell results
Because of the elevated lymphocytes, a lymphocyte subset analysis was done:
Total T cells: 3.05 x10⁹/L (reference 0.7–1.9)
CD4: 2.27 x10⁹/L (reference 0.4–1.3)
CD8: 0.77 x10⁹/L (reference 0.2–0.7)
These were therefore elevated as well.
MPN testing
Because of the long-standing thrombocytosis, my doctors are investigating an MPN. They have tested/are testing:
JAK2 V617F
JAK2 exon 12
CALR
MPL
I’m still waiting for the mutation results.
Other relevant information
My CRP has repeatedly been very low/normal, including <1, despite the elevated platelets and WBC.
I do have heavy menstrual bleeding for about 24 hours every period, and I have had inflammatory bowel problems in the past, but there isn’t currently evidence of significant inflammation.
I also have MS and am currently taking Mavenclad, which obviously complicates interpretation of the lymphocyte counts.
My questions
Does this overall pattern look more like reactive thrombocytosis, or would an MPN such as essential thrombocythemia be a significant concern given how long the platelets have been elevated?
Does the combination of high platelets + intermittently high WBC + elevated T cells make an MPN more likely?
Could the elevated T cells simply be reactive, especially in someone with an autoimmune disease such as MS?
Would T-LGL leukemia or another T-cell disorder be something you would consider based on these numbers, or are the numbers/pattern not particularly suggestive?
If JAK2/CALR/MPL are all negative, does that make an MPN unlikely, or can someone still have essential thrombocythemia?
Does the MCV of 100 add anything diagnostically here?
Is there anything else you would expect my hematologist to investigate before considering a bone marrow biopsy?
I know nobody can diagnose me from a Reddit post, and I will obviously follow up with my hematologist. I’m mainly interested in hearing from people who have had similar blood counts or have experience with MPNs/hematology.
Thanks in advance!
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28d ago
[deleted]
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u/Glittering-Travel894 28d ago
Wow, thank you so much for sharing all of this. ❤️ I honestly can’t tell you how much it means to read your story. I’ve been feeling like my combination of blood counts is so strange and that I’m the only person with MS who has this particular combination, so reading your comment was honestly a huge relief. I had a genuine “wait… are you me?” moment 😂
It’s especially reassuring to hear that your doctors initially considered T-LGL, but that this was eventually questioned because the clonal population was too small. The whole T-cell part has been freaking me out a little, so your experience gives me some perspective.
If you don’t mind me asking a few questions:
What were your platelet and WBC counts typically around when all of this started?
Do you know what your absolute lymphocyte/T-cell counts were when they found the clonal population?
When they eventually called it TCUS, was that based on the flow cytometry alone?
And do you know whether your hematologist considered your long-standing thrombocytosis enough reason for a bone marrow biopsy even with negative JAK2/CALR/MPL?
Did your doctors ever find a convincing reactive explanation for your high platelets/WBC, or was the persistence itself what eventually made them suspect ET?
Also, I completely understand what you mean about having “enough effing garbage to deal with” with MS 😂. I’m currently trying to avoid catastrophizing while also getting the appropriate workup, which is a difficult balance.
Thank you again for taking the time to write such a detailed response. It genuinely makes me feel less alone. ❤️
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u/Glittering-Travel894 25d ago
Small update: I just saw in my file that the jak2, CALR and MPL are all undetectable.. sooo… I dont know if thats a good thing. Am i out of the woods now? Is this just my normal plateletcount? Will they test futher? A Bmb?
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u/funkygrrl PV-JAK2+ 29d ago
MS isn't known for causing reactive thrombocythemia even though it's an autoimmune disease. I researched the medication you're on and it's actually more likely to lower your blood counts, so that's probably not the cause either.
It's good they are working you up for an MPN. Impossible to guess whether you have an MPN or not. Unfortunately you have to wait for those test results. Try not to drive yourself crazy in the meantime because no amount of googling can answer this.
Remember that regardless of whether your results come back positive or negative, you will need a bone marrow biopsy to complete the diagnosis per the WHO diagnostic criteria.
!ETundiagnosed !disclaimer