[SlimMoe]

Was IgA kappa, now IgM kappa - what's it mean?

by SlimMoe on Sat Aug 12, 2017 11:48 am

Previous protein electro­phoresis had IgA kappa since diagnosis. Most recent results now show IgM kappa in both regions. Is this an issue to worry about? What is the significance?

This stuff is way over my head.

[Multibilly]

Re: Was IgA kappa, now IgM kappa - what's it mean?

by Multibilly on Sat Aug 12, 2017 1:44 pm

Hi SlimMoe,

I assume that you are still smoldering and haven't undergone a transplant or any drug treatment for myeloma, right?

Does your immunofixation test also indicate that you still have monoclonal IgA kappa, or does the test result say that you only have monoclonal IgM kappa? If your test results indicate that all of your monoclonal protein is now purely IgM, it sounds like you may have experienced an "isotype switch". If your test results show the presence of both IgM and IgA monoclonal proteins, then this instead sounds like a case of "oligoclonal banding".

These two phenomena sometimes happen after a stem cell transplant, but they can also occur at any time during the course of the disease. In general, I'm pretty sure that both phenomena don't negatively affect one's prognosis - at least based on what I've read. But this would obviously be something you would want to discuss with a myeloma specialist.

First, I might suggest getting re-tested in a few months to see if the test results were truly accurate and that you did actually experience one of the above phenomena. Labs can screw up tests more often than you might think.

Secondly, I would go back and look at your previous and current lab results. Do you know what your new serum quantitative IgA and IgM values and IgA and IgM M-spike values are in com­pari­son to your previous lab results? Also, what has your serum and kappa and lambda free light chain values been doing since the previous test and the most recent test?

If it turns out that you actually are now an IgM smoldering patient, there are some additional things to be on the lookout for that IgG and IgA smoldering patients don't typically worry about. This is a really good article on the subject of IgM plasma cell disorders:

J Mikhael, "Ask the Hematologist: A Diagnostic Approach to Patients with an IgM monoclonal protein," The Hematologist, Sep 15, 2014 (full text of article)

Hope this helps.

[SlimMoe]

Re: Was IgA kappa, now IgM kappa - what's it mean?

by SlimMoe on Sat Aug 12, 2017 6:15 pm

Thanks so much for your help. Like I said, this stuff is over my head. I'm still defined as smoldering. No treatment except for osteoporosis.

2016 interpretation:

M components present, previously identified by immunofixation as subtypes of IgA Kappa (Beta 1 and Beta 2 regions). IgG Kappa is co migrating in the Beta 2 region. M components are co migrating in the Beta 1 and Beta 2 regions, therefore peak1 and peak2 quantitations are only an approximation. Previous M component concentrations were 1.34 g/dL (peak1 in Beta 1) and 0.18 g/dL (peak2 in Beta 2) on Aug 9, 2016.

M COMP 1 (g/dL) 1.28 g/dL
M COMP 2 (g/dL) 0.19 g/dL

MPeak ID 1 IgA Kappa (Beta-1 region)
MPeak ID 2 IgA Kappa

IgG Immunoglobulin 683 mg/dL 700-1600 mg/dL
IgA Immunoglobulin 1595 mg/dL 70-400 mg/dL
IgM Immunoglobulin 34 mg/dL 40-230 mg/dL

Kappa FLC, Serum 253.99 mg/L 3.30-19.40 mg/L
Lambda FLC, Serum 9.05 mg/L 5.71-26.30 mg/L
Kappa/Lambda FLC Ratio, S 28.07 0.26-1.65

2017:

M components present, previously identified by immunofixation as subtypes of IgA Kappa (Beta 1 and Beta 2 regions). M component is co migrating in the Beta 1 region, therefore peak1 quantitation is only an approximation. Peak2 in Beta 2 is unquantifiable. Previous M component concentrations were 1.28 g/dL (peak1 in Beta 1) and 0.19 g/dL (peak2 in Beta 2) on Dec 9, 2016.

MPeak ID 1 IgM Kappa
MPeak ID 2 IgM Kappa

M Comp 1 (g/dL) 1.18 g/dL
M Comp 2 (g/dL) UNQUANTIFIABLE g/dL

IgG Immunoglobulin 604 mg/dL 700-1600 mg/dL
IgA Immunoglobulin 1382 mg/dL 70-400 mg/dL
IgM Immunoglobulin 30 mg/dL 40-230 mg/dL

Kappa FLC, Serum 267.68 mg/L 3.30-19.40 mg/L
Lambda FLC, Serum 10.37 mg/L 5.71-26.30 mg/L
Kappa/Lambda FLC Ratio, S 25.81 0.26-1.65

Again, thanks.

[Multibilly]

Re: Was IgA kappa, now IgM kappa - what's it mean?

by Multibilly on Sat Aug 12, 2017 11:45 pm

Thanks for posting your lab results. It seems like you are misinterpreting the results. In this context , the "M components" are two different IgA kappa m-spikes, not a new IgM m-spike. In other words, an "M-component" is just another name for an "m-spike" and doesn't mean "IgM". You basically have two different IgA kappa m-spikes, instead of the typical, single m-spike. This "biclonality" happens from time to time and isn't anything to worry about.

Also, for reasons I won't go into here, IgA m-spike measurements tend to be inaccurate and are sometimes overstated. But having said that, your 2016 IgA m-spike value is the total of M Comp 1 + M Comp 2 = 1.28 g/dL + 0.19 g/dL =1.47 g/dL.

Lastly, since you are IgA-type smoldering myeloma, you may want to consider asking your doctor about using the new "Hevylite assay" to track your clonal IgA values. Hevylite does a better job of tracking IgA clonality than does the normal serum protein electrophoresis test.

Last edited by Multibilly on Sun Aug 13, 2017 5:47 pm, edited 1 time in total.

[SlimMoe]

Re: Was IgA kappa, now IgM kappa - what's it mean?

by SlimMoe on Sun Aug 13, 2017 1:42 pm

This is the difference I saw that gave me concern:

2016:

MPeak ID 1 IgA Kappa (Beta-1 region)
MPeak ID 2 IgA Kappa

2017:

MPeak ID 1 IgM Kappa
MPeak ID 2 IgM Kappa

So this in not actually a change?

[Multibilly]

Re: Was IgA kappa, now IgM kappa - what's it mean?

by Multibilly on Sun Aug 13, 2017 5:42 pm

Ah, I didn't catch that subtlety in your immunofixation results.

I may be wrong, but I think your 2017 immunofixation results:

MPeak ID 1 IgM Kappa
MPeak ID 2 IgM Kappa

were incorrectly reported and should have been been reported as IgA kappa instead of IgM kappa. I say this because of your other 2017 total immunoglobulin values:

IgG Immunoglobulin 604 mg/dL 700-1600 mg/dL
IgA Immunoglobulin 1382 mg/dL 70-400 mg/dL
IgM Immunoglobulin 30 mg/dL 40-230 mg/dL

Your total IgA value is high at 1382 mg/dL (1.382 g/dL), yet your total IgM value is low at 30 mg/dL (0.03 g/dL). In 2017, you have a total M-spike value of 1.18 g/dL (1180 mg/dL).

Keep in mind that your M-spike + healthy immunoglobulin = total immunoglobulin. It would therefore be mathematically impossible for you to have an IgM M-spike of 1180 mg/dL (1.18 g/dL) when your total IgM value is only 30 mg/dL (0.03 g/dL). However, it would be perfectly in line to have an IgA M-spike of 1180 mg/dL (1.18 g/dL) with a total IgA value of 1382 mg/dL (1.382 g/dL).

By the way, assuming you are indeed IgA-type smoldering myeloma, you would be classified as having immunoparesis since both your IgM and IgG are actually suppressed.

In any case, this would be something good to discuss with your specialist. And, again, I would also suggest talking about the new Hevylite test. IgA M-spike measurements can be a bit tricky to get right since other proteins in your blood can reside in the same regions that IgA M-spikes occupy. The Hevylite assay gets around this problem.