Aims: Overlap syndrome of ANCA-associated vasculitis (AAV) and scleroderma (SSc) is rare with conflicting data on renal outcomes. We describe the clinical characteristics and treatment outcome of ANCA-associated glomerulonephritis (AAG) in SSc patients followed at a single center.
Materials and methods: We conducted a retrospective study of 3,570 patients in our SSc database to identify SSc patients who subsequently developed AAV with renal involvement. Patient demographics, serology, renal function, renal histology, and treatment outcomes were assessed.
Results: Of the 3,570 patients, we identified 7 patients who developed acute glomerulonephritis, and all were ANCA positive. The mean age at SSc diagnosis was 47 years, 4 patients were female, and 6 had diffuse SSc. Anti-nuclear antibody (ANA) was positive in all. Mean time of onset of AAV from time of diagnosis of SSc was 6 years, and all were myeloperoxidase (MPO) positive. Patients presented with hematuria, proteinuria, with or without rise in serum creatinine, and all patients had biopsy-proven crescentic glomerulonephritis. One patient required dialysis at presentation. Five patients were treated with cyclophosphamide and steroids, and 2 were treated with rituximab and steroids. Of the 7 patients, 4 did not receive maintenance immunosuppression. Three patients died, and 1 of them experienced relapse with fulminant alveolar hemorrhage.
Conclusion: AAG in SSc is rare, with disease manifestation and course similar to that of AAV. This case series demonstrates that disease remission can be achieved with standard induction therapy. Vasculitis relapse can occur, and similar to idiopathic AAV, maintenance immunosuppression should be initiated to maintain remission. .