BACKGROUND: Patients with multiple myeloma often have Bence Jones proteins composed of free monoclonal light chains of the kappa or lambda type in their urine. Usually, these light chains exist as monomeric or dimeric forms, but rarely, larger molecules, such as tetramers, have been reported in the serum. METHODS AND RESULTS: We report the presence of trimeric complexes of lambda light chain dimers in a patient who was diagnosed with a free lambda light chain multiple myeloma 2 years earlier and subsequently underwent a stem cell transplant. Recently, the patient presented with a large serum M-spike (23 g/L) by protein electrophoresis. The spike consisted of monoclonal lambda light chains without a heavy chain. The urine contained only 8 mg of lambda light chain in a 24-h specimen. Quantitative analysis of the serum and urinary free light chains (FLCs) indicated the probability of larger aggregates of FLCs. Size-exclusion chromatography, electrophoresis, analytical ultracentrifugation, and mass spectrometric studies of the serum revealed almost exclusively the presence of trimolecular aggregates of lambda light chain dimers without other multimeric species. CONCLUSION: Monoclonal lambda light chains may present as hexameric aggregates that cannot be cleared by renal excretion.
BACKGROUND:Patients with multiple myeloma often have Bence Jones proteins composed of free monoclonal light chains of the kappa or lambda type in their urine. Usually, these light chains exist as monomeric or dimeric forms, but rarely, larger molecules, such as tetramers, have been reported in the serum. METHODS AND RESULTS: We report the presence of trimeric complexes of lambda light chain dimers in a patient who was diagnosed with a free lambda light chain multiple myeloma 2 years earlier and subsequently underwent a stem cell transplant. Recently, the patient presented with a large serum M-spike (23 g/L) by protein electrophoresis. The spike consisted of monoclonal lambda light chains without a heavy chain. The urine contained only 8 mg of lambda light chain in a 24-h specimen. Quantitative analysis of the serum and urinary free light chains (FLCs) indicated the probability of larger aggregates of FLCs. Size-exclusion chromatography, electrophoresis, analytical ultracentrifugation, and mass spectrometric studies of the serum revealed almost exclusively the presence of trimolecular aggregates of lambda light chain dimers without other multimeric species. CONCLUSION: Monoclonal lambda light chains may present as hexameric aggregates that cannot be cleared by renal excretion.
Authors: Lawreen H Connors; Yan Jiang; Marianna Budnik; Roger Théberge; Tatiana Prokaeva; Kip L Bodi; David C Seldin; Catherine E Costello; Martha Skinner Journal: Biochemistry Date: 2007-11-16 Impact factor: 3.162
Authors: Makbule Senel; Fatemeh Mojib-Yezdani; Ulrike Braisch; Franziska Bachhuber; Jan Lewerenz; Albert C Ludolph; Markus Otto; Hayrettin Tumani Journal: Front Immunol Date: 2019-03-29 Impact factor: 7.561