Neuroscience

β2-Microglobulin (β2M) is a small serum protein that constitutes the light chain of the major histocompatibility class I human leukocyte antigen (HLA class I), an integral membrane protein involved in the immune response. The protein is 99 amino acid residues in length and has molecular mass of 12 kDa. β2M is released from the cell surface of HLA class I into the serum and carried to the kidneys for degradation and secretion. In chronic renal failure, β2M accumulates as insoluble amyloid aggregates and causes arthralgias, destructive osteoarthropathies, carpal tunnel syndrome and dialysis-related amyloidosis. Elevated serum β2M levels are associated with poor prognosis in multiple myeloma and lymphoma.