Accumulation of defective immunoglobulin light chains in plasma cells (commonly referred to as "immunoglobulin light chain amyloid" or "amyloidogenic immunoglobulin light chains") (AL (for "amyloid light-chain") amyloidosis, or simply AL)

The accumulation of defective immunoglobulin chains in plasma cells, specifically immunoglobulin light chains, refers primarily to the pathogenesis seen in disorders like systemic AL amyloidosis, multiple myeloma with excess free light chain production ("light-chain myeloma"), and related monoclonal gammopathies. In these conditions, abnormal clonal expansion of plasma cells leads to overproduction—and often misfolding—of monoclonal immunoglobulin fragments. These fragments can aggregate into insoluble fibrils that deposit in tissues such as kidneys, heart, liver, nerves, and more—causing progressive organ dysfunction and failure if untreated. This process is not itself a single molecular entity but represents an aberrant outcome from dysregulated antibody synthesis by neoplastic/plasma cell clones. While therapies exist that reduce production at the source—the malignant clone—there are no drugs that directly target already accumulated defective/misfolded chains; thus this is considered not a canonical therapeutic target but rather an important pathogenic mechanism underlying several hematologic diseases.

Other names

Amyloidogenic immunoglobulin light chainLight chain amyloidosis proteinAL proteinMisfolded immunoglobulin light chain

Inhibition or destruction of clonal plasma cells to reduce production/secretion of pathogenic light chains. Proteasome inhibition induces apoptosis in malignant plasma cells. Immunomodulatory drugs enhance immune-mediated clearance.