ANCA-associated vasculitis in the United Arab Emirates: a 17-year case series with review from Gulf literature

BACKGROUND:
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare and severe autoimmune disease characterized by pauci-immune necrotizing vasculitis.


OBJECTIVES:
The study aims to explore the frequency, clinical characteristics, and management of AAV patients in two tertiary centers in the United Arab Emirates (UAE) over 17 years.


DESIGN:
A retrospective observational case series


SETTING:
Two tertiary centers in the UAE


METHODS:
Patients diagnosed with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), or eosinophilic granulomatosis with polyangiitis (EGPA) from 2008 to 2024 were included. Demographic, clinical, laboratory, histopathological information, treatment, complications, relapses, and mortality were collected. ANCA testing for anti–proteinase 3 (PR3) and anti–myeloperoxidase (MPO) antibodies was performed using enzyme-linked immunosorbent assays. Descriptive statistical analysis was performed to summarize the data.


MAIN OUTCOME MEASURES:
Subtype distribution, organ involvement, ANCA positivity, relapse, and mortality rates.


SAMPLE SIZE:
Twenty-six patients


RESULTS:
We identified 26 AAV patients with a median age of 52.5 years. The majority were females (58%, n=15), and half were locals. The most common AAV subtype was microscopic polyangiitis (50%, n=13), followed by granulomatosis with polyangiitis (38%, n=10) and eosinophilic granulomatosis with polyangiitis (12%, n=3). ANCAs tested positive in nearly all of these cases. The most common clinical manifestations of AAV were constitutional symptoms with renal and pulmonary involvement. The induction therapy included corticosteroids, rituximab, cyclophosphamide, mycophenolate mofetil, and plasma exchange. The most prescribed maintenance medications were corticosteroids and azathioprine. The overall relapse rate was 31%, and the overall mortality rate was 19% (n=5).


CONCLUSION:
In our cohort, MPA was the most common subtype, being predominantly associated with P-ANCA/MPO-ANCA positivity. Notably, few studies from the Gulf region have addressed this topic. It's unclear whether this finding reflects low occurrence or potential underdiagnosis and, thus, points to unmet needs and a significant gap in the understanding of AAV. Multicenter studies are needed to validate these results and improve AAV management in Middle Eastern populations.


LIMITATIONS:
Retrospective design with small number of participants