[DallasGG]

Clonal plasma cell percentage

by DallasGG on Sun Feb 15, 2015 8:11 pm

I had a bone marrow biopsy a week ago and was told that I was still in remission based on the bone marrow biopsy and other blood test results. I asked my doctor what percentage of clonal plasma cells I had in my bone marrow.

My doctor told me that I had 1-2% clonal plasma cells in my bone marrow and that normal is anything less than 5%. I always thought that a "good result" for the clonal plasma cell percentage in the bone marrow is zero. Clearly, my understanding was wrong. After thinking about it , I realized that common sense would have told me that someone without multiple myeloma has plasma cells in their bone marrow. And that there is a "normal" percentage that is greater than zero.

I thought I understood this, but clearly I don't understand it very well.

Does anyone know of a good resource that can describe what the clonal plasma cell percentage from a bone marrow biopsy means and what a desirable percentage is? Or can you give your understanding of this percentage?

Also, does a bone marrow biopsy identify the "bad" plasma cells if they exist?

[Multibilly]

Re: Clonal plasma cell percentage

by Multibilly on Sun Feb 15, 2015 8:51 pm

DallasGG,

This does get confusing, doesn't it? Based on your plasma cell counts alone (note the other factors to also consider below), it sounds like you may be in "complete remission", but not "stringent complete remission".

Dr. Voorhees boils down the definition of the degrees of remission in these comments:

"Remission simply means that there has been a decrease in the amount of myeloma as a result of your treatment.

In myeloma, there are many different kinds of remission. For those patients with a measurable "M spike," a partial remission means that the M spike has decreased anywhere from 50% to 90% of the level it was immediately prior to treatment.

A very good partial remission refers to a 90% or greater decrease in the M spike.

A complete remission means that the M spike is no longer detectable and there are less than 5% plasma cells on a repeat bone marrow biopsy.

A stringent complete remission meets all measures of a standard complete remission, but also includes a normal serum free light chain ratio and the plasma cells on the bone marrow biopsy must be polyclonal.

For those myeloma patients who have non-secretory disease (no M spike) and for those with light chain myeloma, similar definitions of partial remission, very good partial remission, and complete remission are in place."

- P Voorhees, "Re: Remission, what does it mean?," Jan 13, 2013.

[gardengirl]

Re: Clonal plasma cell percentage

by gardengirl on Sun Feb 15, 2015 10:46 pm

Here's where I get confused. This is from the same thread:

The IgG, IgA, and IgM measures the total levels of these kinds of antibodies in the blood -- those that are made by the myeloma (in your husband's case, IgA lambda antibodies) and those made by normal plasma cells. The M spike is a measure of the amount of antibody made by the specifically by the myeloma.

Your husband's IgA at diagnosis was over 4000 mg/dL (4 g/dL) and the IgA lambda M spike was 2.2 g/dL. That means that of the 4 g/dL of IgA, 2.2 g/dL of that was myeloma IgA."

So by doing math (and I know IgA is an exception, so assuming any immunoglobulin), 4-2.2=1.8 or 1800 mg/dL is NOT made by the IgA myeloma, right?

But upper range limit for IgA is 414 mg/dL. So what accounts for the excess IgA (~1400 mg/dL) if it's not myeloma? What am I missing?

[Multibilly]

Re: Clonal plasma cell percentage

by Multibilly on Mon Feb 16, 2015 12:05 am

Hey Gardengirl,

I might throw out a couple of things to consider.

One is that M-spike measurements of IgA are not very reliable, so the actual IgA M-spike level might be smaller than what was reported by the SPEP. Secondly, there are multiple conditions that can elevate one's quantitative IgA level, not just the presence of monoclonal IgA from multiple myeloma. And, the quantitative IgA lab result could have also been off.

As one of my docs likes to say "if you don't like your lab results, just wait a bit and get re-tested"

But I honestly don't know if any of these are in play here and one's doc would really need to comment.

[DallasGG]

Re: Clonal plasma cell percentage

by DallasGG on Mon Feb 16, 2015 1:33 pm

Thanks for the information.

I emailed my doctor this morning and asked for a copy of my last 2 bone marrow biopsies. The one from December 2013 (right before my transplant) showed 0% clonal plasma cells. Note: I originally had 80% in my first BMB after my diagnosis in June 2013. The one from this month showed 1-2% clonal plasma cells.

So, like you said Multibilly, it looks like I've gone from a stringent complete remission in December 2013 to a complete remission now, based on Dr. Voorhees remission descriptions.

Have other people experienced a slow creep up in the percentage of clonal plasma cells in the bone marrow from one year to the next? And is it something I need to be concerned with at this point?

[blair77]

Re: Clonal plasma cell percentage

by blair77 on Tue Feb 17, 2015 12:34 am

I would say no concern as BMBs from different sites can have different results. Who's to say that your BMB pre-transplant might have had 1-2% clonal cells elsewhere? Bone marrow is not uniform throughout your body, so readings can be different from one area to the next. 1-2% is quite small.

[DallasGG]

Re: Clonal plasma cell percentage

by DallasGG on Tue Feb 17, 2015 2:12 am

Blair, thanks for your explanation. I know that I'm still in pretty good shape as far as my multiple myeloma goes. I have to be thankful for that. I try not to put too much weight into each new blood test or BMB result, no matter how hard that may be at times.