Ask the Lab Scientist Q1 2020

Questions submitted by readers and answered by the CLL Society Medical Advisory Board

By Susan Leclair, PhD, CLS (NCA)

My 63-year-old sister just dx with CLL and has the zap-70 marker.  Can you explain a little more about it?

Answer from Dr. LeClair:  Zap 70 is a piece of the cell membrane that is usually associated with T cells.  Since most CLL is a B-cell disorder, you shouldn’t have a lot of Zap 70 on your cells.  This suggests that her cells may be a bit more “confused” than the classic cell seen in B-cell CLL.  This confusion can cause more issues such as infections or more long-lasting infections, more fatigue, etc., she might want to ask her physician how he/she will be following it.   By the by, Zap 70 testing is rather tricky so follow up testing should probably be for Immunoglobulin heavy chain genes (IvHG) as this is a more stable and reliable test.

 

I am in my early 60’s with Cll that diagnosed five years ago.  Still on W&W.  This year my labs have been steadily increasing, but only have minor symptoms of moderate night sweats and deep muscle aches.  My question is my recent lab showed 1% metamyelocytes with .17 abs count.  Is this of any significance or is it normal?  It’s never been reported in any of my other labs.  Thanks.

Answer from Dr. LeClair:  Metamyelocytes are a less than fully matured neutrophils.  Think of them as 13-16-year-old kids.  Yes, they can do a lot of things that their fully matured colleagues can do but there are also things they cannot do.  Usually, they remain in the bone marrow until they get more functional (think of a 19-21-year-old).  It is at that stage that they leave the marrow and enter the blood stream. 

So what does that mean?  Because the metamyelocyte is rather close to its older cousin, even in the healthy marrow can allow 1-2 to escape every now and again.  For a marrow which is under stress (for any reason), it is not a huge surprise to see them occasionally in the peripheral blood. The items your physician considers to be important include how often, how many and are there any younger versions also slipping out of the marrow.  Too many, too often and most importantly less mature forms suggest that the stress has increased and might bear watching.

 

When your FISH test says TP53 deletion does it mean one thing?  Or are there variations?  Is further testing of TP53 required (I hope that makes sense)?  The FISH test doesn’t say anything about 17p but it does say 13q deletion and well as the TP53 deletion.  Thank you for any help.

Answer from Dr. LeClair:  As with all genes, multiple changes in the structure of a protein can and do occur.  With all of these “mutations, some have been proven to be irrelevant to health, some are found only in malignancies, and still others for which we have no real knowledge.  As a consequence, FISH testing has been constructed to test for only the mutations known to be connected to specific conditions. So, the long answer to your question is that there are more mutations, but additional testing will give you no usable information. 

 

If monocyte level is 14.  Eosinophil 4.  Neutrophil 48.  Hb 12.9.  Female and except monocyte everything is normal what is diagnosis?

Answer from Dr. LeClair:  No one can give a diagnosis save your physician but, I can tell you there is nothing here that is significant.  Monocytes typically use the blood stream to move from one site to another so slight increases in monocytes can be seen quite frequently.

 

Are B-CLLs deficient in vimentin from the very beginning?  Are they created without vimentin?  Or, since they live so much longer than healthy Bs, does their vimentin content perhaps start out normal and get depleted over a long lifespan?  (IOW, are older B-CLLs more fragile than younger ones (either because of vimentin or other reasons?  The Deuterium papers on age & dynamics are pretty exciting but I haven’t seen anything address this specifically.  FWIW, a neat 2017 study, https://doi.org/10.1073/pnas.1614661114, found oxidized, surface-bound vimentin as a useful marker of senescence.)  BTW, thanks very much for the pointers on CBC via flow cytometry.  They got me started on a lot of reading about gating strategies and the operation of hemocytometers in general.   In retrospect I wish I had led with the more generally patient-interesting question, “In my first CBC report after CLL diagnosis, it mentioned that smudge cells were present.  But no subsequent said that. Why not?”  My own observations confirmed very high counts of smudge cells – indeed many more intact lymphocytes than the reported ALCs suggested.  It made me wonder if CBCs, by being rough on cells, might tend to undercount ALC in CLL pts simply because B-CLLs, being more fragile, were more apt to lyse along with the RBCs inside the machine and be discarded. In the end I learned after talking with Quest (my local lab) that a simpler explanation was at work: there are many different lab request codes for “CBC,” only some of which including a manual differential.  And Quest only reports observations like smudge cells on these.  So my initial CBC was manual (it even says so on the report, now that I go back to read it properly!) and all subsequent CBC’s were auto.  I know ALCs are the result of a bajillion factors, up until the time disease progression begins to become dire.  (I’m W&W.)  But I guess I have to add to that list of complications, the rough handling a B-CLL nuclear membrane might receive in the aftermath of a lysis buffer.  If you’ve heard other patients wonder about when smudge cells are reported, that might be a topic that’s of more general interest.  I’m generally a few too many steps ahead of myself for my own good!

Answer from Dr. LeClair:  Regarding vitmentin, early examination seems to suggest that vimemtin is more of a consequence rather than an initiator of abnormality.  Since vimemtin deficiency is seen in many benign conditions as well as in some malignancies, its role in anything other than general suppression of immune function and cellular repair is not commonly supported.  Could vimemtin be used in some type of therapy?  Possibly, although it presence in so many normal cells would make this quite difficult.

As to smudge cells, you are correct about the fragility of malignant nuclei in the presence of the instrument’s lysing agent.  But it also true that a wise variety of unfriendly environments (over‑mixing, changes in temperature, making a blood smear, etc.) 

The typical lysing agent destroys all the red cells and all of the white cells as well.  The earlier instruments counted nuclei and could come up with absolute lymphocyte count by assuming that all of the round/oval nuclei were lymphocytes.  White cells have nuclei, so it was the number of cells with intact nuclei that was the WBC.  If the nuclei were destroyed (as in the case of CLL), the cell is not counted, resulting in a falsely decreased count. 

Since the earlier instruments counted nuclei, they could determine the absolute lymphocyte count by assuming that all of the round/oval nuclei were lymphocytes.  Later models still have the counting error but the manner of using chemicaleutroohil, staining and fluorescent antibodies will give you a valid differential. 

 

What is the significance LDH Lactate Dehydrogenase in CLL?

Answer from Dr. LeClair:  Lactate dehydrogenase or LD in the modern parlance is an enzyme that is found in nearly every cell in the body.  Whenever cells re damaged or die, all of their enzymes are released into the blood stream.  So increases in LD mean that somewhere, for some reason, some cells are not doing well. In CLL, there could be several potential reasons. 

1. CLL cells are, of course, damaged by their own DNA.
2. For some CLLs, there can be inappropriate immune functions – misformed antibodies that don’t work or don’t work correctly can cross react with totally innocent antigens and cause harm.
3.  For others, T cell function is altered, thus other immune functions involving macrophages, eosinophils, and other cells increase the inflammatory process. 
4. Then, of course, there are issues concerning medications.

I would add that several other medical issues unrelated to CLL can elevate the LDH including almost problems with almost any organ in the body such as the lungs, heart, kidneys, livers, and more.

 

What does leukemia is seen to be 90% involved in the bone marrow mean? This was the result of a biopsy done to assess why there were frequent compression fractures.

Answer from Dr. LeClair:  Fractures can be seen in those bones in several different ways.

One is the situation in which you have active marrow (locations vary by age and the degree of damage from the disease) causing pressure from the inside out.  Picture in your mind a standard plain manicotti.  The bone structure is the actual pasta shell while the marrow fills the space in the middle of the pasta.  The marrow expands during the overwhelming cell number increase and this increase “pushes” against the inner wall of the pasta.  This increased pressure is similar to trying to over fill the manicotti. The more you try to push more filling in, the more likely you will cause longitudinal breaks in the pasta.  

Now, transfer that image from pasta to a human bone. As the pressure of the malignant cells increases, the bone will try to stretch, causing thinning of the bone.  Finally, the bone is no longer strong enough to do its job.

The second possibility is a situation in which the body is no longer capable of maintaining proper calcium balance.  Loss of calcium results in loss of bone strength and bone can eventually break/crush.

 

Dear Dr, I just got some weird results that I can’t find anywhere.  Have you ever heard of 21p? Also why is my IGHV mutated when I have high zap 70 and an evolution in the clones?  Also is 6 q the same as sec 63 myb?   Do you have any other thoughts?  Thanks so much!  I really appreciate this.

Answer from Dr. LeClair:  I know it can be terribly upsetting to see confusing results. 

21P is a deletion of part of the upper “arm” of chromosome 21.  Most of the that portion of the chromosome is devoted to specific RNA function that allow for the making of several cellular proteins.  This means that the cells have trouble either making or maintaining proper cellular metabolism and will get damaged more easily or will die off too soon.

Part of chromosome 6 lower “arm’ contains a set of genes that control on/off regulators. One of those genes is the se 63 myb.

Finally, it is true that usually a negative ZAP70 will be seen within a positive IVgH mutation, so this is not a common situation.  But it can occur and is part of that insanely annoying aspect of malignant cells that they often do irrational things. 

Each of these tests describes a part of the properties of your malignant cells.  Your physician is best situated to put each of these results into the full picture of your status.

 

My Lymphocyte reading is %18.2 percent and monocyte is at 10%. Is this cause for concern?

Answer from Dr. Koffman:  Only pay attention to absolute count, not the percentage.  Without the absolute counts, it is impossible to comment.

See this from Dr. LeClair:  https://cllsociety.org/2019/06/ask-the-lab-scientist-q2-2019/

 

 

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Susan Leclair, PhD, CLS (NCA) is Chancellor Projessor Emerita at the University of Massachusetts Dartmouth; Senior Scientist, at Forensic DNA Associates; and Moderator and Speaker, PatientPower.info – an electronic resource for patients and health care providers.