Hi Duckboy, welcome to this forum although I know you’d prefer not to be here.
The majority of people with MGUS do not go on to develop myeloma, so hopefully you’ll be in this camp, although I understand your desire to understand enough to get a perspective on what might be.
There are a number of subtypes of myeloma, which are ‘immortal’ plasma cells. Myeloma UK have some brilliant information leaflets which you may have found on the site, if not, have a look.
The different subtypes are monitored in slightly different ways.
The main subtypes are heavy chain myeloma which create paraproteins- usually IgG or IgA (but others are possible) and light chains, although the lightchain figures are not usually regarded as significant. The next common subtype is light chain only myeloma which only produces part, “an arm” of the heavy chain, either Kappa or Lambda light chains. I take it that you have kappa lightchain MGUS.
Healthy people do not have paraproteins in their blood, but it is normal to have a low level of light chains. When you see the normal range, and compare that to one’s own, it is very alarming. I’ve got IgG lambda myeloma and at diagnosis had 10x the normal level of Lambda lightchains (c260) which felt concerning- until I found out that patients with lightchain myeloma often have lightchains of over 1,000 at diagnosis and I’ve met someone whose lightchains were 22,000 at diagnosis.
In lightchain myeloma often it’s the ratio between kappa and lambda lightchains that is more significant than the numbers themselves.
I hope this is helpful & explains why a 15% rise may not be worrying to your Dr.
In terms of what to look out for, a broad approach is to watch out for so called “CRAB” symptoms, high calcium levels, results indicating that you are developing kidney problems, anaemia or bone pain. In addition to these there may be other parameters to keep an eye on, but these can be pretty individual. I keep an eye on my haemoglobin, haematocrit and neutrophils as these tend to be below normal, but as long as they are stable, my Dr isn’t worried.
