What is the Difference Between Kappa and Lambda Light Chains?

Kappa and lambda light chains are two types of light chains found in immunoglobulin molecules, which are proteins produced by plasma cells. They are covalently linked to heavy chains to form immunoglobulins, but they also exist as free light chains (FLCs) in the bloodstream. The main differences between kappa and lambda light chains are:

1. Molecular weight: In serum, kappa FLCs exist predominantly as monomers with a molecular weight of 22.5 kDa, while lambda FLCs exist as dimers with a molecular weight of 45 kDa.
2. Glomerular filtration rate: The size difference between kappa and lambda light chains results in a differential glomerular filtration rate, leading to a ratio of kappa to lambda FLCs of 1:1.6 in serum.
3. CDR3 regions: Kappa and lambda light chains have different physicochemical and structural properties, particularly in their complementarity-determining region 3 (CDR3).
4. Presence in different immunoglobulin types: There are 10 variations of immunoglobulins for myeloma patients, including IgA kappa, IgG kappa, IgM kappa, IgD kappa, IgE kappa, IgA lambda, IgG lambda, IgM lambda, IgD lambda, and IgE lambda.

The detection of FLCs is important for diagnosing and monitoring various monoclonal gammopathies, such as multiple myeloma, Waldenstrom macroglobulinemia, nonsecretory myeloma, smoldering multiple myeloma, and monoclonal gammopathy of undetermined significance. The kappa/lambda ratio can indicate disease progression or remission.

Comparative Table: Kappa vs Lambda Light Chains

Here is a table comparing the differences between kappa and lambda light chains:

Kappa and lambda light chains are part of the immunoglobulin structure, with each antibody containing two identical light chains. They are found on different chromosomes and have distinct physicochemical properties. During myeloma conditions, immunoglobulins grow rapidly and produce more light chains than heavy chains. The balance of kappa and lambda together is called the kappa/lambda ratio, which can indicate a change in levels of disease.