Clinical Characteristics and Prognosis Analysis of Kidney Injury in Idiopathic Multicentric Castleman Disease (TAFRO Syndrome)

Background: The TAFRO subtype is a distinct form of idiopathic multicentric Castleman disease (iMCD), characterized by thrombocytopenia, anasarca, fever, renal impairment, and organomegaly. This study aims to elucidate the clinical characteristics and prognosis of renal injury in patients with iMCD-TAFRO. Methods: This retrospective cohort study evaluated hospitalized patients diagnosed with iMCD-TAFRO. Renal injury was defined according to iMCD renal injury criteria. Survival analysis was conducted using the Kaplan-Meier method. Results: This study included 50 patients with iMCD-TAFRO, of whom 36 were male (72%), with a mean age of 46 ± 15 years. The key manifestations were serous effusion (100%), lymphadenopathy (100%), thrombocytopenia (100%), and renal injury (88%). Renal injury presented as reduced urine output (88.6%), hematuria (56.8%), proteinuria (70.5%), and elevated serum creatinine (sCr) levels (97.7%). Nine renal biopsies revealed endothelial cell disease in eight and one case of necrotizing nephritis. Thirty-two patients were diagnosed with acute kidney injury (AKI), and 50% of them required renal replacement therapy. AKI patients demonstrated decreased urine output and higher C-reactive protein and D-dimer levels, which correlated with the severity of renal damage. However, no significant difference was observed in interleukin-6 levels. Treatment strategies included glucocorticoids (88%), bortezomib and cyclophosphamide (62%), and IL-6 monoclonal antibodies (40%). This resulted in a complete biochemical response in 64% of the patients and a biochemical partial response in 6%. Additionally, 20% of patients either died or voluntarily discharged. During a median follow-up period of 439 days (range: 150-937 days), 75% of the patients who received renal replacement therapy were able to discontinue dialysis. Furthermore, 86% of patients returned to normal sCr levels within three months. No significant differences in survival rates were found between patients with or without dialysis. Conclusion: Patients with iMCD-TAFRO syndrome exhibit significant renal involvement, with AKI associated with a more severe inflammatory response. Active treatment targeting the underlying disease, with renal supportive care, is associated with improved patient prognosis.