Free Kappa and Lambda Light Chains Plus Ratio
(Serum free light chains)
B-cell carries either kappa- or lambda-light chains on its surface (a distinctive marker).
Normal, polyclonal B-cells are a mixture of kappa-B-cells and lambda-B-cells (one marker or the other)
When malignant B-cell clone proliferates it will lead to b-cell population consisting
of either only kappa- or only lambda-B-cells. (one marker, and not the other, suggests malignancy)
Adapted from med4you.
Serum free light chains as marker for CLL?
Dr Furman writes: It is important to remember that there are over 75 different prognostic markers for CLL. Serum free light chains is just another one. Any time there is an increase in the number of B cells, there can be an increase in the serum immunoglobulins and serum free light chains. The serum immunoglobulins are the antibodies produced by CLL cells. Every antibody contains two heavy chains linked to two light chains. The serum immunoglobulins are the complete molecule. You can also have heavy chains alone (uncommon) or light chains alone (common) secreted. The serum free light chains that are measured just represent the light chains from the antibody.
Most CLL patients are hypogammaglobulinemic (low antibodies). Some of these patients will still have elevated light chains, but many will have low values for these as well. The light chains are usually filtered in the kidney and do not accumulate very much in the serum and it has only been the last 15 years that we have been able to measure the serum free light chains. The times the light chains accumulate are usually due to increased secretion or decreased clearance by the kidneys. Thus, light chains can be a surrogate for kidney function. Not necessary the cause of kidney dysfunction, but just not cleared because the kidneys are not working properly.
It is extremely rare for CLL patients to develop kidney problems due to light chains, but not so uncommon for myeloma and Waldenstrom's patients to develop these problems There are two types of light chains, kappa and lambda, and it is almost only lambda that can cause the problem, sometime as resulting in amyloid.
I encourage patients to not worry about light chains as prognostic markers and only use them in patients with kidney disease that might be attributable to them.