Since 2013, I have been getting Flow Tests periodically to monitor whether any new mutations might be occuring. I have noticed that my CD19 marker has been changing as follows.
Can someone tell me what this marker means and what the observed trend might mean or suggest? I assume that one might need to interpret these results in concert with other parameters.
Also, I thought I saw that someone out there might have an instructional video explaining how to interpret/understand Flow Test results. Can someone help.
53% ( April 2013), 11%( January 2014), 10% (April 2014), 22% ( July 2014), 16% ( Nov 2014), 20% (Feb. 2015), 18% ( Jan. 2016), 29% ( Aug 2016), 29% (June 2017), 23% (June 2018). Note: Have been getting these test performed via the Veterans Administration Health System in the USA.
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markjeep51
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The CD19 marker identifies B-lymphocytes, so it would be interesting to have your corresponding lymphocyte count blood test results. Jm954 may be able to shed some light on why the big changes.
Dr Susan Leclair has explained the purpose of various blood tests in a range of videos, but this is the closest I have found where flow cytometry is mentioned: secure.patientpower.info/vi...
Thanks AussieNiel: I did try to send a chat message to JM954; not sure if it went through. FYI, below is what I sent:
AussieNeil suggested I send you my question concerning my CD19 marker measurements. I have had several CD19 measurements since my CLL diagnosis in 2013. In summary I do not understand the variability of these measurements and what this may mean. I am 13q mutated with other favorable parameters. The following is a summary of my CD19 measurements along with WBC and Absolute Lymphocyte count (ALC).
(Date of Flow Test, CD19 %, WBS, ALC)
April 2013, 53%,14.5 k/uL, 3.7 k/uL
Jan,2014, 11%, 11.68, 4.04
Apr 2014, 10%, 10.8, 4.84
July 2014, 22%, 11.43, 5.14
Nov 2014, 16%, 13, 4.98
Feb 2015, 20%, 12.59, 5.77
Jan 2016, 18%, 14.29, 6.34
Aug 2016, 29%, 13.66, 6.92
June 2017, 29%, 15.55, 8.9
June 2018, 23%, 15.6, 8.6
Fundamentally, I do not know what this CD marker means. For example, does this marker represent the % of cancerous B cells I have? I have been unable to get an understandable answer from my oncologist. I have been getting these Flow Test performed by the Veterans Administration in the USA. Any help you can give me to better understand what this CD parameter really means and the above trends would be greatly appreciated. PS: Am a retired engineer and enjoy trying to understand this kind of stuff. Thanks Mark
I think there are two elements to your question about CD19.
The first is regarding the numbers in your results and the second is the clinical significance of any change.
Any one CD result should never be considered in isolation as it's the pattern of CD results that is important in diagnosis and monitoring of any haematological malignancy.
CD should be a relatively simple test to do as part of your FLOW analysis. However, even simple tests are subject to error and variability (coefficient of variation) and more so when there are lots of steps in the process and analysis.
Your lymph count is still quite low and this in itself is a difficulty because these cells have to be separated from all the other cells in your blood so that they can be analysed. It's easy to get a representative sample when you have 100+ lymphs but not so easy at 4,6,or 8. Remember, you also have normal T and B cells in there as well so the number of CLL cells is less than your total count. When the cell count is so low the coefficient of variation or standard deviation from the mean of your sample results (I wouldn't normally use these terms but you're an engineer!) can be 50% or more. To try to eliminate some variation it's important to have the test done by the same lab, using the same techniques each time.
Here's a bit more about the technical stuff, it's old but most of it is still correct today.
CD19 expression is significantly lower in CLL cells than normal B cells and is involved with cell signalling. As far as I can tell it has little significance in CLL diagnosis and monitoring as it is present on all B cells with the exception of mature plasma cells.
She has a large number of videos on lab testing on Patient Power - you may want to pick and choose from this long list of subjects to help understand. On occasion she answers specific questions directed to her through Patient Power and other online sites:
Flow cytometry has a few uses in CLL diagnosis, but running repeat tests is odd. I suuggest you look for a specialist CLL doctor outside the VA system...I realise that may not be possible...🤔
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