Evaluation of Light Chain Removal Rates in Blood Purification Therapy for Light Chain Cast Nephropathy

Acute kidney injury is a crucial prognostic factor for multiple myeloma. The most common cause is light chain cast nephropathy. The primary pathology of light chain-induced acute kidney injury involves obstruction of distal tubules due to the interaction of free light chains (FLCs) with Tamm-Horsfall protein produced there. Based on this pathology, chemotherapy is used to suppress the production of FLCs. Recently, combined blood purification therapies to remove existing FLCs have been used. However, the extent to which FLCs are removed by blood purification therapy remains unclear. We investigated the dialysis removal rates under various conditions and found that hemodialysis achieved 16% removal, plasma exchange 75%, and online hemodiafiltration varied from 20% to 31%. Although online hemodiafiltration is less effective than plasma exchange, it is a viable option that does not require albumin infusions or lead to infections. Despite hematologic remission, renal recovery was limited by a high number of casts, severe interstitial fibrosis and tubular atrophy, and the delay in treatment initiation.