Flow cytometry - dim, moderate or bright?

Hello all

Just wondering if anyone can shed a little light on how I should read some flow cytometry results, please?

I am in the UK (I guess different indicators/symbols may be used in other countries...) but I would like to know what the "+" symbol means when it follows a CD number, e.g. CD19+, CD23++, etc?

How many "+" symbols indicate dim, moderate and bright expression? I mean, is CD23++, for example, moderately or brightly expressed?

Also, I note some of the CD numbers on the flow cytometry report are followed by a "+" symbol over a "-" symbol (sorry but I can't reproduce the symbol here....it's either the limitations of my phone or simply me being a bit thick!).

Anyway...if anyone can explain the significance of these symbols I'd be most grateful.

Having CLL is proving to be one huge learning curve!☺

Thanks very much!

Debs.

5 Replies

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  • Flow cytometric immunophenotyping separates CLL from other lymphomas, like mantle cell, Burkett's, Marginal zone, follicular etc. by a specific 'fingerprint'... known as a differential...

    CLL is typically characterized as CD19+, CD5+, CD23+, CD22−, CD79b− , FMC7-with weak expression of sIg.

    BUT... there are CLL patients who are different... this is like an average situation...

    You may have other clusters of differentiation, CD, some institutions add a few they think are important... bit of a fashion statement....

    So, flows can also tell something about the B cell population... for example CD38 is a surrogate marker for IGHV gene mutation.... under 30% you are mutated... good...over 30% you are unmutated, not so good... ZAP70, does a similar thing....

    Bright, dim and moderate... describe the amount of a particular cell surface protein. Generally, in CLL CD20 is dim, however for some patients, usually Trisomy 12, it might be bright. CD20 is the target of a treatment called a CD20 monoclonal antibody, like Rituxan... so brighter, means more, which means it will work better in the 'bright' patients...

    Anyway... hope this helps... here are two links that will show the complexity of this stuff...

    So

    + is positive...

    ++ is more positive

    - is negative

    +/- we don't really know...

    When there is a range...they use dim, moderate and bright...

    Differential Pathology

    surgpathcriteria.stanford.e...

    Everything about flow cytometry, you don’t need to know ;-)

    bloodjournal.org/content/11...

    Here is a pretty good booklet from the UK, it is getting a bit old... like me...

    but will give you some basics

    leukaemialymphomaresearch.o...

    ~chris

  • Hi

    Thanks very much for the explanation and links - very useful! (Even though I'd rather not have CLL I have to admit I find the whole subject quite fascinating!😮)

    However, sometimes more info leads to more questions so I hope you don't mind 2 more, please...

    1. Is there a "+++" and/or a "++++" indicator in regular use in flow cytometry? Most of my results are showing with either "+" or "++" but I'm not sure whether this means "dim"/"moderate" or whether it suggests "moderate"/"bright"....

    e.g. if results show CD5++, does this mean "moderate" or "bright"?

    2. Does "bright" CD20 always indicate Trisomy 12 or can patients have "bright" CD20 without having Trisomy 12?

    Thanks again for your help. It is very much appreciated! ☺

    Keep well!

    Debs.

  • I'm not certain what the extra pluses mean.. usually it is marked positive with a percentage... these are all determined by gating on a computer, so it may just be the way the software writes the results... ask your doctor or pathologist...

    Bright CD20 does not indicate trisomy 12, but Trisomy 12 determined by a FISH panel, often have bright CD20, but not always...

    Most other FISH markers are usually 'dim' for CD20, but not always...

    As you learn more about CLL/SLL you will find a lot of overlap with other lymphomas and many grey areas...

    Here is a good overview of Flow Cytometry, explains the various ways it can be used for cell counting, gating etc...

    flowbook.denovosoftware.com

    ~chris

  • Blimey!

    You're not wrong when you say there are lots of grey areas....

    I will speak to my doctor (haematology) at our next appointment for an explanation of the symbols used on my flow cytometry report.

    There is much to learn but, personally speaking, I'm finding the reading/research is definitely helping me to get to grips with my diagnosis of CLL!

    Thanks again for your input ☺

    Keep well.

    Debs.

  • Glad to help Debs.... the more you learn the more you realize what we don't know about CLL/SLL...

    Why is CLL called a leukemia and SLL a lymphoma when they are the same cancer, with very different presentations? One 'wet' ..in the blood, one 'dry' in the nodes...

    And from there it just gets more complex... 😜

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