Immunoglobulin lambda light chain dimer (λ-FLC dimer)

The Immunoglobulin lambda light chain dimer is a protein complex formed by two lambda light chains that are produced by plasma cells. While light chains are normally part of a complete antibody, they are often produced in excess as free light chains (FLCs); lambda FLCs have a high propensity to form stable dimers via covalent or non-covalent interactions (PMID: 21652331). In plasma cell dyscrasias like AL amyloidosis, these dimers misfold and aggregate into insoluble amyloid fibrils that deposit in vital organs, particularly the heart and kidneys, leading to progressive organ failure (PMID: 32661324). Modern therapeutic approaches target these dimers either by suppressing the underlying plasma cell clone or by using specialized monoclonal antibodies designed to bind and clear the misfolded proteins from tissues (PMID: 33433457). Monitoring the levels of these dimers in the serum is a critical diagnostic and prognostic tool for managing monoclonal gammopathies.

Other names

Lambda free light chain dimerFree lambda light chainBence-Jones proteinλ-FLCMisfolded lambda light chain

Monoclonal antibodies such as anselamimab and birtamimab bind to cryptic epitopes exposed on misfolded or aggregated lambda light chains to promote their clearance by phagocytic cells. Other indirect therapies involve proteasome inhibitors or anti-CD38 antibodies to deplete the plasma cells producing the light chains.