Surface marker study?

[S001]

This was in one of the diagnosis reports. I haven't understood what this means - "Surface marker study - Scanty blasts gated show myeloid phenotype. (Blasts are positive for CD34, CD117, CD33 and CD13)."

What are these CD34, CD117, CD33 and CD13?

And I was also curious about chromosonal abnormalities. Some people have no chromosonal abnormalities, but still have low RBC's, WBC's and/or platelets. Why or rather how? Some easy to understand explanation for this?

[Greg H]

I'm not educated enough to explain what those results mean, but I can explain that the CDs (it stands for "cluster of differentiation") are all molecules found on the surface of cells -- in this case, I gather, on the surface of your father's blasts. The markers can be used in the lab to distinguish one type of cell from another -- for example, to distinguish a T-cell lymphocyte from a B-cell lymphocyte.

I believe some CDs on blasts are thought to be associated with particular bone marrow diseases. But that's about as far as my knowledge goes on this point. Perhaps someone else is better informed.

My original understanding of MDS was that MDSers have stem cells with abnormal chromosomes, which make defective blood cells, which result in poor blood counts. But lots of MDS sufferers don't seem to have chromosomal abnormalities, as you have noticed.

One explanation is the theory that, in some patients, it's not the chromosomal abnormalities that cause the problem, but instead an auto-immune problem in which the patient's immune system attacks the marrow, all kinds of nasty chemicals get released, which lowers blood cell production and also causes the damage to the stem cell chromosomes. If that goes on long enough, you do in fact wind up with damaged chromosomes that make defective blood cells. And you go from being a lower risk MDS patient to a higher risk patient.

Probably both of these descriptions are right, but in different subsets of patients. For example, some folks may have chromosomal damage as a result of exposure to benzene or other toxins, as a result of advanced age, or as a result of the deterioration of the telomeres on the ends of their chromosomes and that sets off their MDS. Other folks may have the auto-immune variety of the disease.

Everything I have read about this ailment leads me to believe it's not one disease, but several related rare diseases that all currently have the same name.

Take Care!

Greg

[S001]

Hmmmm, thank you so much for that. Your explanations are spot on..

[Birgitta-A]

Hi S001,
As Greg wrote for example CD34 is a cell surface antigen expressed on human hematopoietic progenitor cells – very early stem cells that can make all kinds of blood cells.
http://www.copewithcytokines.de/cope.cgi?key=cd34

Here is a review article about chromosome aberrations in MDS - as you can see all groups have found different results. I like Haase’s results best because he thinks that mine aberrations (12p- and –X) are OK but unfortunately I have 2 aberrations and that is worse than having one of them.
http://www.springerlink.com/content/a8487147628700n4/
Kind regards
Birgitta-A

[S001]

@Birgitta-A - These links are good. Thank you for these!