[dianaiad]

light chain assay question

by dianaiad on Thu Mar 14, 2013 10:43 pm

How often does it happen that a free light chain assay can be absolutely normal (as in, smack dab in the middle of normal ranges all the way through) and still have stage II Multiple myeloma, with a protein level of 4390 and 75% plasma cell presence in the bone marrow? Where can I go find information on this?

thanks.

[Dr. Peter Voorhees]

Re: light chain assay question

by Dr. Peter Voorhees on Fri Mar 15, 2013 4:16 am

Dear Dianaiad,

95 - 97% of symptomatic myeloma patients have an abnormal serum free light chain ratio at diagnosis. 88 - 90% of smoldering myeloma patients have an abnormal free light chain ratio and for MGUS it drops to 33 - 44%.

The fact that the ratio and light chain levels are normal is not a bad thing. In fact, extremely low and extremely high free light chain ratios have been associated with a worse prognosis.

So, consider yourself unique and lucky!

Pete V.

[dianaiad]

Re: light chain assay question

by dianaiad on Fri Mar 15, 2013 11:12 am

Oh, I figured that this was a GOOD thing! It's just...a weird thing. I was simply wondering how often it happened, and what it meant. I understand that monitoring free light chain levels and ratios is one of the ways treatment efficacy is measured. Indeed, isn't the free light chain assay one of the early indicators of relapse and/or response? If, for me, that can't be done using free light chain tests, how will we do it?

[JoeyNutz]

Re: light chain assay question

by JoeyNutz on Fri Mar 15, 2013 8:19 pm

Anecdotally, is there any difference between the 95-97 percent of symptomatic myeloma patients who have an abnormal serum free light chain ratio at diagnosis and those that do not?

In my case, I had a high M-spike (5) - IgG kappa - at diagnosis - that is now less than 0.5 with rev and dex. But my FLC ratio has always been normal.

[dianaiad]

Re: light chain assay question

by dianaiad on Sat Mar 16, 2013 8:33 pm

Hi, Joey...

Nice to know that I"m not utterly unique... I'm curious as well...is there any difference between those who have normal light chains...and the vast majority that do not?

[Multibilly]

Re: light chain assay question

by Multibilly on Sun Mar 17, 2013 8:32 am

This doesn't really answer your question, but it does give you a lot more insight into FLC testing and the percentages of those patients who have multiple myeloma and normal FLC ratios. See p 18 for stats. It's an interesting read regardless, especially in regards to the role of FLC measurement wrt diagnosis and prognosis.

http://www.aacc.org/SiteCollectionDocuments/Events/Expert%20Access/2006/SerumOct06/ExpertAccessMonoclonalGammopathies100806.pdf

[Dr. Peter Voorhees]

Re: light chain assay question

by Dr. Peter Voorhees on Sun Mar 17, 2013 11:59 pm

An abnormal free light chain result can be the first sign of disease progression, but you have a readily identifiable "M-spike" that should pick up a relapse in an appropriate time frame. I would still consider spot checking serum free light chain levels over the course of your treatment and post-treatment monitoring to ensure that there is no evidence of "light chain escape." This is a scenario where a myeloma that was previously making an intact antibody/immunoglobulin starts only making the free light chain component of the antibody.

As far as prognosis, a normal ratio would be considered a good thing. Only the more extreme ratios are associated with more aggressive disease.

Pete V.