The role of plasmapheresis in the treatment of patients with multiple myeloma-related kidney injury

AIM: Kidney injury is a common, serious complication of multiple myeloma and an important cause of mortality. The main cause of kidney injury in multiple myeloma is cast nephropathy, which occurs as a result of excessive production of monoclonal M proteins and their precipitation in the renal tubules. The main treatment approach in light chain cast nephropathy is to suppress the production of these free light chains, which are toxic to the renal tubules, with antimyeloma agents. However, until the effectiveness of antimyeloma treatments is observed, light chains will continue to cause toxicity to the kidneys. Theoretically, removal of these free serum light chains by plasmapheresis will reduce the burden on the kidneys and accelerate the recovery of kidney functions. Our aim in this study is to examine the effect of plasmapheresis on cast nephropathy by comparing patients who received antimyeloma treatment along with plasmapheresis due to light chain cast nephropathy in Akdeniz University Hospital Clinical Apheresis Unit, and patients who did not receive plasmapheresis and received only antimyeloma treatment. MATERIALS and METHODS: Pre-treatment and post-treatment data of 71 patients who applied to Akdeniz University Hospital with multiple myeloma and renal failure between 01.01.2014 and 31.06.2023 and received plasmapheresis and antimyeloma treatment; Akdeniz University Hospital Clinical Apheresis Unit files, patient files and the hospital database were examined and scanned retrospectively. In our study, renal response was defined as a patient experiencing a greater than 50% decrease in creatinine levels and becoming dialysis independent. RESULTS: 30 patients who received plasmapheresis treatment along with antimyeloma treatment and 41 patients who received only antimyeloma treatment were included in the study. The patients' creatine values were compared at the time of diagnosis/before apheresis, at the end of the 1st cycle of antimyeloma treatment and at the end of the 4-5-6st cycles. When the creatine values were compared before treatment/apheresis and at the end of the 4-5-6st cycles, renal response was observed in 19 of 39 patients (48.7%) who received plasmapheresis and antimyeloma treatment and in 18 of 30 patients (60%) who received only antimyeloma treatment. ( The end of 4-5-6st cycles creatine values of 2 patients who received only antimyeloma treatment could not be reached because one patient exited the study and we were unable to follow up with the order.) Death occurred within the treatment period in 6 of 30 patients (20%) who received plasmapheresis and antimyeloma treatment and in 3 of 41 patients (7.3%) who received only antimyeloma treatment. The incidence of hemodialysis at the time of diagnosis in patients receiving only antimyeloma treatment is 19.5% (41/8). This rate is 3.3% in patients receiving plasmapheresis and antimyeloma treatment (30/1). The incidence of hemodialysis at the end of the treatment decreased to 14.4% (41/6) in patients receiving only antimyeloma treatment, while it did not change in patients receiving plasmapheresis and antimyeloma treatment (30/1). CONCLUSION: Although a significant renal response rate was obtained when both groups were examined separately, no significant difference was observed in terms of renal response, death during the treatment period, and dialysis dependence when the two groups were compared. Thus, in our study, no significant superiority of plasmapheresis could be demonstrated in terms of renal response, dialysis dependence, and survival during the treatment period. We think that achieving a significant renal response rate in both groups is related to early hydration, correction of hypercalcemia, avoidance of nephrotoxic agents and early initiation of antimyeloma treatment. KEYWORDS: Multiple myeloma, plasmapheresis, cast nephropathy, free light chain