Kidney Transplant Outcomes in Coatomer Protein Complex Subunit Alpha (COPA) Syndrome: Report of Five Patients.

COPA (coatomer protein complex subunit α) syndrome is a rare inborn error of immunity associated with constitutive activation of type I interferon signaling. Organ inflammation and damage (eg, lungs, kidneys, joints) usually develops early in life. Kidney involvement occurs in a subset of COPA syndrome patients, with the potential for rapid progression to kidney failure. Through an international collaboration, we identified COPA syndrome patients who developed kidney failure and underwent a kidney transplantation. The aim of the present report was to describe (1) the kidney involvement at presentation, (2) the immunosuppressive strategies used before and after transplant, (3) the kidney graft outcomes, and (4) the evolution of the underlying COPA disease after transplantation. Five COPA syndrome patients were included. Kidney failure manifested at young age (range, 5-40 years). Kidney involvement was heterogenous between patients (ANCA-associated vasculitis-like disease, lupus or immune complex-mediated glomerulonephritis or overlapping phenotypes), and all had advanced histological damage at clinical presentation. Pulmonary disease of variable severity was also present in all patients. Kidney disease responded poorly to multiple lines of immunosuppression, justifying kidney transplantation between the ages of 7.5 and 42 years. After a follow-up of 10 months to 12 years, we report favorable graft outcomes in all patients (CKD stage 2-3b), although 1 patient developed polyomavirus infection (skin, kidney graft) and another died of progressive lung disease.