[jhorner]

Level of involved light chain (lambda) is decreasing

by jhorner on Mon Feb 15, 2016 12:04 pm

Hello,

I am a smoldering patient who has some minimal evidence of evolving disease, specifically immunoparesis that has continued to worsen (my IgA is 46 and IgM is 28), and new cytogenetics results that are abnormal compared to results from a bone marrow two years prior that had no cytogenetic abnormalities.

This being said, my M-spike has been stable during this time at 1.03-1.3 g/dl. What is strange is that I have IgG lambda paraprotein according to the bone marrow results, but my IgG lambda keeps going down. The results of the last three free light chain assays are as follows:

Lambda - 11.3 mg/dl ; 9.4 mg/dl ; 8.9 mg/dl

While my kappa is going up.

Kappa - 9.5 mg/dl ; 10.4 mg/dl; 11.3 mg/dl

Now, I was once biclonal – my first bone marrow showed lambda paraprotein with small amounts of kappa – but the last bone marrow biopsy showed only lambda. Is there any scientific explanation for why this might happen and any prognostic significance?

Due to being biclonal, I was told that light chains should be used to measure disease pro­gression instead of M-spike, so does a decrease in lambda light chains over time mean that the disease isn't progressing in spite of the abnormal cytogenetics of t(11:14) with monosomy 13 and immunoparesis?

Has anyone else had this occur?
JBH

[Multibilly]

Re: Level of involved light chain (lambda) is decreasing

by Multibilly on Mon Feb 15, 2016 3:37 pm

Jhorner,

I am not a pathologist, but I think you can attribute your very minor free light chain fluctuations to the inherent inaccuracies of the free light chain assay itself (different batches of assay reagents, different equipment, etc) and/or normal day-to-day fluctuations in one's free light chain markers (you will get different free light chain readings on the same lab equipment if you simply get retested at different times on the same day). I therefore think you would need to see some much more dramatic changes in your free light chain numbers in order to begin to read anything into these fluctuations.

To give you an idea of how much my free light chain values have varied over 3+ years as a smoldering multiple myeloma patient without treatment, see these numbers:

K/L Kappa Lambda
14 9.10 0.63
20 11.10 0.89
33 13.2 0.38
33 14.8 0.49
17 16.1 0.97
20 14.8 0.68
20 12.0 0.60
100 17.3 0.14
25 21.0 0.78
25 19.7 0.78
33 22.8 0.72
25 18.4 0.61
20 14.7 0.74
20 14.1 0.72
20 13.1 0.71
20 12.8 0.70
14 14.2 0.10
17 12.3 0.75
17 17.1 0.10
17 11.3 0.65
17 11.4 0.63

[jhorner]

Re: Level of involved light chain (lambda) is decreasing

by jhorner on Mon Feb 15, 2016 4:18 pm

Thank you very much! I appreciate you sharing your results as that does provide some helpful insight. So it would seem that my light chains are stable as is my M-protein, but my bone marrow biopsy percentage increased by 10% (recognizing this is unreliable due to pockets of plasma cells), my cytogenetics are now abnormal, and my immunoparesis is worsening. It makes me wonder if my myeloma is oligosecretory. However, I think there is a cut-off of measurable M-protein at 1 g/dl and mine has been as "high" as 1.3 ...

I had a really difficult time convincing doctors that my smoldering multiple myeloma was making me sick because these numbers are so low and they still seem to be disproportionate to other myeloma defining factors.

Thank you so much again.
JBH