Immunoglobulin Lambda Light Chain (IGLV1-44/IGLV1-40)
Monoclonal protein produced by clonal plasma cells — near-universal lambda restriction
- Expression
- Monoclonal overproduction
- Evidence level
- established
Role in pathogenesis
Over 95% of POEMS cases have lambda light chain restriction. The variable regions are highly restricted to IGLV1-44*01 (~80%) and IGLV1-40*01 (~20%), with conserved stereotypic amino acid changes in CDR1 and FR2 regions. This extreme restriction, unique among plasma cell disorders, suggests antigen-driven selection. The monoclonal protein itself may contribute to neuropathy through direct nerve damage or immune-mediated mechanisms.