#634 Prognosis is still poor in patients with posttransplant C3 glomerulopathy: a multicenter cohort

Abstract

Abstract Background and Aims Data on patients with posttransplant recurrent or de novo C3 glomerulopathy (C3G) are limited. We therefore aimed to analyze features and outcomes of patients developed posttransplant C3G. Method In this retrospective multicenter study conducted across 3 centers, we collected the data of kidney transplant recipients (KTRs) who were diagnosed with posttransplant recurrent or de novo C3G between 2014-2023 and followed for at least 3 months after the diagnosis. Demographic, clinical, laboratory and histopathological characteristics of patients were retrieved from the databases of participating centers. Primary outcome was defined as death-censored graft loss necessitating dialysis or re-transplantation, and secondary outcome was complete (CR) or partial remission (PR). CR was the recovery of baseline eGFR and proteinuria of <0.5 g/g. PR was ≥50% reduction of proteinuria (and to <3 g/g in patients with nephrotic-range proteinuria at baseline) plus stabilization or improvement in kidney function. Results Eleven patients were identified, and 10 with follow-up data were included. Detailed features of patients were shown in the Table. Five (50%) were male, and mean age at the time of transplantation (KTx) was 33.2 ± 8.5 years. Nine KTRs (90%) were diagnosed with recurrent C3G and the etiology of primary kidney disease was not known in one patient. Majority of KTx were performed from living donors (9.90%). One patient had a history of T-cell mediated rejection before posttransplant C3G, which had showed good response to anti-rejection treatment. Posttransplant C3G was diagnosed after a median of 26 (3-85) months after KTx, and mean age was 36.8 ± 9.1 years. Mean hemoglobin, serum creatinine, serum albumin, and proteinuria at the time of diagnosis were 10.5 ± 1.8 g/dl, 1.9 ± 0.7 mg/dl, 4.1 ± 0.5 g/dl, and 1.1 ± 0.9 g/g, respectively. Monoclonal disorders were excluded by using serum and urine electrophoresis and serum free light chain assays in all KTRs. Serum C3 was low (67.1 ± 29.7 mg/dl, ref: 90-180 mg/dl) in 7 of 8 KTRs with available data (87.5%). Further immunosuppressive treatment was administered in 9 cases. Eculizumab was used in 8, and 1 patient was treated with pulse steroids and therapeutic plasma exchange. Median duration of treatment was 14.5 (3-24.3) months. Four patients (44.4%) who were treated with eculizumab showed CR. After a median of 32 (9.5-82) months, 5 KTRs (50%) experienced graft loss despite eculizumab use in 3 of them. No adverse events attributed to treatment were observed. Conclusion Prognosis is still quite dismal in patients with posttransplant C3G despite the use of eculizumab. Better treatment options are urgently needed.