Subcutaneous daratumumab in recurrent posttransplant focal segmental glomerulosclerosisAleš Rigler, Andreja (Avtor) Belčič Mikič, Tanja (Avtor) Bošnjak, Matic (Avtor) Arnol, Miha (Avtor) kidney transplantationprimary focal segmental glomerulosclerosisdaratumumabRecurrent primary focal segmental glomerulosclerosis (FSGS) after kidney transplantation requires prolonged treatment, often with unsatisfactory results. We report 2 cases of FSGS recurrence that achieved remission with subcutaneous daratumumab and propose novel mechanisms of its action that demonstrate efficacy in this disease. The first patient was a 51-year-old woman who experienced early FSGS recurrence 1 month after transplantation. With regular biweekly plasma exchange, her daily proteinuria was 1-1.5 g, and the estimated glomerular filtration rate was 43 mL/min/1.73 m2. Although 2 doses of rituximab depleted CD19/20 B lymphocytes, they were ineffective in reducing proteinuria, leading to the reintroduction of plasma exchange. Based on histological persistence of FSGS at the 1-year surveillance biopsy, subcutaneous daratumumab treatment was initiated, which led to a rapid decrease in proteinuria and disease remission. The second patient was a 25-year-old woman with a second relapse of FSGS 7 years after transplantation, which was immune adsorption dependent as rituximab was ineffective in inducing remission. A kidney biopsy performed 2 years later showed persistence of FSGS as well as chronic active antibody-mediated rejection. Daratumumab treatment was initiated using the chronic active antibody-mediated rejection treatment protocol. With this treatment, daily proteinuria decreased from 6 g to 0.3-0.5 g, and immune adsorption was discontinued. In conclusion, daratumumab shows promise in controlling recurrent FSGS in selected kidney transplant recipients with potential mechanisms beyond plasma and natural killer cells.20262026-09-10 14:32:22Neznano32427sl