Thrombotic microangiopathies after kidney transplantation in modern era: nosology based on chronology.

BACKGROUND: Thrombotic microangiopathies (TMAs) are rare but can be severe in kidney transplant. recipients (KTR). METHODS: We analysed the epidemiology of adjudicated TMA in consecutive KTR during the. 2009-2021 period. RESULTS: TMA was found in 77/1644 (4.7%) KTR. Early TMA (n = 24/77 (31.2%); 1.5% of all KTR) occurred during the first two weeks ((median, IQR) 3 [1-8] days). Triggers included acute antibody-mediated rejection (ABMR, n = 4) and bacterial infections (n = 6). Graft survival (GS) was 100% and recurrence rate (RR) was 8%. Unexpected TMA (n = 31/77 (40.2%); 1.5/1000 patient-years) occurred anytime during follow-up (3.0 (0.5-6.2) years). Triggers included infections (EBV/CMV: n = 10; bacterial: n = 6) and chronic active ABMR (n = 5). GS was 81% and RR was 16%. Graft-failure associated TMA (n = 22/77 (28.6%); 2.2% of graft losses) occurred after 8.8 (4.9-15.5) years). Triggers included acute (n = 4) or chronic active (n = 14) ABMR, infections (viral: n = 6; bacterial: n = 5) and cancer (n = 6). 15 patients underwent transplantectomy. RR was 27%. Atypical (n = 6) and typical (n = 2) haemolytic and uremic syndrome, and isolated CNI toxicity (n = 4) were rare. Two-third of biopsies presented TMA features. CONCLUSIONS: TMA are mostly due to ABMR and infections; causes of TMA are frequently combined. Management often is heterogenous. Our nosology based on TMA timing identifies situations with distinct incidence, causes and prognosis.

De novo and relapsing necrotizing vasculitis after COVID-19 vaccination.

We describe five cases of severe necrotizing vasculitis following the RNA-based vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including four relapsing anti neutrophil cytoplasmic antibodies (ANCA) vasculitis, 27 days (1-60) after vaccination and one patient with quiescent chronic hepatitis B and de novo polyarteritis nodosa (PAN) 21 days after vaccination. Ten other cases were reported to the French national pharmacovigilance database: six patients with ANCA-associated vasculitis and four patients with PAN (first symptoms 19 days on average after vaccination). Five of these 10 patients developed kidney dysfunction. In conclusion, coronavirus disease 2019 (COVID-19) vaccines can be associated with de novo or recurrent ANCA vasculitis or PAN. Attention should be paid to patients with known ANCA vasculitis or patients with a history of hepatitis B infection.