% JAK2 and Neutrophils (I think!)

[Paul123456]

A while back one of my Hems said that % JAK2 rises/falls with, I think he said Neutrophils but might have been Lymphocytes. I’m sorry but I can’t remember the relationship but that the only truly accurate JAK2 measurement is directly from a BMB.

Hoping that our resident expects such as Hunter and EP can shed some light on this?

Best Paul

[PhysAssist]

Hi Paul,

This is what I found re: your question:

Key Points:

The sensitivity and specificity of detecting the JAK2 p.V617F mutation in peripheral blood [PB] are both 100% compared with bone marrow [BM].

The JAK2 p.V617F allele burden measured in PB is equivalent to that in BM aspirate (R2 = 0.991; P < .0001).

Here: ncbi.nlm.nih.gov/pmc/articl...

I hope you found this helpful.

PA

[Paul123456]

Thanks very much. I’ll double check with the Hem who told me about the link (with Neutrophils) next time we talk. I may have assumed the bit about BMB being the only truly reliable method because the context was my Neuts going up and down, impacting JAK2%.

Best Paul

[PhysAssist]

Also, this may be what the Heme MD was referring to:...Thrombopoiesis [development of thrombocytes = platelets] is particularly stimulated by low allele burden, as an inverse relationship between allele burden and platelet count has been reported. This is in keeping with the low level of mutant alleles found in ET patients, whose clinical phenotype is dominated by thrombocytosis....

found it here:

ncbi.nlm.nih.gov/pmc/articl...

But what it actually saying is that either early in the development of a MPN disease course, or in some mutations with low allele counts for other reasons, the primary effect is to increase platelet expression/production [=ET], vs moderate allele counts being more often associated with PV, and very high allele counts being associated with MF either primary or post-PV.

[EPguy]

Sorry I missed this one. Physassist has the reports. There have been various over the years, and the modern ones do find a close match. I believe mine was 5 points apart, 14 on blood, 19 on BMB. I plan to ask further at my next appt.

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But I checked a bit further. The relevant reports showed that which blood part got used matters. These are clustered around~2007. This is old news for an allele that was only ID'd in 2005. Anyway there apparently was a time when Jak2 was measured via different blood elements, neutrophils and CD34+ . Looking up CD34+ they are all in that same old timer period. Could be your Dr is familiar with this history.

pubmed.ncbi.nlm.nih.gov/187...

<< In ET and PV, mean CD34(+) cell JAK2(V617F) allele burdens were lower than the corresponding neutrophil allele burdens,>>

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My guess is this has been standardized in recent practice as here:

More recently we get alleles via "ddPCR" and it seems they use "whole blood" rather than certain parts. I also saw a modern report using just serum (the liquid part).

<<DNA was obtained out of 400 μL of whole blood>>

ncbi.nlm.nih.gov/pmc/articl...

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[EPguy]

This is old, but maybe topical to the current thread on Hunter's allele response. Have you learned any more from your Hem? Does it lead to an idea that lowering WBC on IFN relates to reduced allele?