A case of lambda type tetramer Bence-Jones proteinemia.

A 50-year-old woman was found to have an extramedullary plasmacytoma of the thoracic vertebrae and a bone marrow plasmacytosis of 72%. In the serum of this myeloma patient, M-bow percipitin line was seen only with anti-lambda chain serum, but not with antisera against mu, alpha, gamma, delta, ipsilon and kappa chains. Gel filtration of the serum on the Sephadex G-200 column demonstrated the monoclonal lambda chain in the A-fraction along with transferrin and suggests a molecular weight of 88,000 and a tetrameric light chain. Bence-Jones protein has never been detected in the patient's urine.