Recovery of kidney function following delayed use of theralite™ dialyzer in a patient with myeloma cast nephropathy

We report the case of a 60- year- old man who presented with newly diagnosed multiple myeloma complicated by biopsy-proven acute cast nephropathy, requiring hemodialysis, plasmapheresis and chemotherapy. After remaining dialysis dependent for 5 weeks, a high cut-off (HCO) dialyzer, intended to use for the removal of plasma substances with a molecular weight of up to 45 kDa such as free light chains, was introduced to his outpatient 4-hour hemodialysis regimen with an increase in treatment frequency to 4 sessions per week. Following 6 weeks of dialysis with the HCO dialyzer, serum levels of free κ light chains declined by more than 75%. Concurrently, he recovered kidney function and discontinued dialysis. He subsequently received a successful autologous stem-cell transplant. We discuss the potential merit of using the HCO dialyzer late in the course of the care of patients with myeloma cast nephropathy who are dialysis dependent.