Light-chain removal by plasmapheresis in myeloma-associated renal failure

BACKGROUND: Although plasmapheresis has been recommended to reverse nephrotoxic elevations of serum free light chains (sFLCs), there are scant published data on removal of sFLC measured with modern assays. STUDY DESIGN AND METHODS: sFLC levels were recorded in two patients with myeloma-associated renal failure receiving multiple plasmapheresis procedures. RESULTS: In one patient, presenting with acute renal failure 8 months after diagnosis of kappa-LC myeloma, 16 plasmapheresis procedures neither reduced sFLC levels (percent removal ranging from -70% to +40%) nor improved renal function. In another patient who presented with leukemic immunoglobulin A-lambda myeloma and acute renal failure, sFLC decreased by 30 to 60 percent after each plasmapheresis procedure, but rebounded within 5 to 10 hours. Renal failure occurred despite plasmapheresis, and hemodialysis was required. CONCLUSIONS: In both patients, plasmapheresis failed to effectively lower sFLC levels. The results provide initial biologic data supporting the conclusions of a recent randomized multicenter clinical trial in which plasmapheresis was an ineffective adjunct to chemotherapy for myeloma-associated acute renal failure.