Immunoglobulin lambda light chain (free) (λ-FLC)

Immunoglobulin lambda light chains are small protein components of antibodies produced by plasma cells. In a healthy state, these light chains are produced in slight excess and circulate as free lambda light chains (λ-FLCs) before being filtered and catabolized by the kidneys (StatPearls, 2023). However, in plasma cell dyscrasias such as multiple myeloma or AL amyloidosis, a malignant clone produces excessive amounts of monoclonal lambda light chains (UniProt, 2024). These excess chains can form toxic aggregates or amyloid fibrils that deposit in organs like the heart and kidneys, leading to severe organ dysfunction and "cast nephropathy" (Mayo Clinic, 2024). While traditional therapies like bortezomib and daratumumab target the plasma cells to stop production, newer agents like anselamimab (CAEL-101) are designed to bind directly to the misfolded light chains to facilitate their clearance (ClinicalTrials.gov, 2024). Monitoring the serum free light chain levels and the kappa/lambda ratio is essential for the diagnosis, prognosis, and assessment of treatment response in these diseases (PubMed, 2022).

Other names

Free lambda light chainLambda-FLCBence-Jones proteinImmunoglobulin lambda light chainIGL

Direct binding and clearance of amyloidogenic light chain aggregates or suppression of light chain production via plasma cell depletion (Journal of Clinical Oncology, 2021).