Demonstration of changes in plasma cell subsets in multiple myeloma

Multiple myeloma (MM) is charac-terized by a malignant prolifera-tion of monoclonal plasma cells in the bone marrow and of their products in serum and/or urine. M-Igs and FLCs are used to monitor disease and treatment. FLCs are found in the urine of 68 % of MM cases. So-called Bence-Jones proteinuria (BJP) and increases of FLCs in serum are associated with disease progression.1,2 Up to 20 % of MM cases have FLC only disease in which light chains in the serum and/or urine is the only immunochemical abnormality found.3 The serum assay for FLCs in MM has been extensively investigated.4 A shift to the secretion of light chains has been associ