From the Guidelines
ANCA vasculitis can be triggered by various factors including infections, such as influenza, and other events like pregnancy. The triggers of Anti-Neutrophil Cytoplasmic Antibody (ANCA) vasculitis are multifactorial and not fully understood, but it is known that relapses can be triggered by many events from an episode of influenza to pregnancy 1.
Triggers of ANCA Vasculitis
- Infections: such as influenza
- Pregnancy: and other events
- Other factors: may also contribute to the development of ANCA vasculitis, but the exact mechanisms are not well understood. It is essential to monitor patients with ANCA vasculitis closely, as relapses can occur, and treatment needs to be adjusted accordingly 1.
Importance of Monitoring
- Regular monitoring: of ANCA, full blood counts, ESR, CRP, renal and pulmonary function tests is necessary to adjust treatment and prevent relapses.
- Multidisciplinary setting: ideally, patients should be managed in a multidisciplinary setting to ensure comprehensive care. Understanding the triggers of ANCA vasculitis is crucial for developing effective prevention strategies and improving patient outcomes 1.
From the Research
Triggers of ANCA Vasculitis
The triggers of Anti-Neutrophil Cytoplasmic Antibody (ANCA) vasculitis are multifactorial and include:
- Genetic factors 2, 3
- Environmental exposures 2, 4
- Infections 2, 3, 5, 4
- Characteristics of the innate and adaptive immune system 4
- Intensity and duration of the injury 4
Role of Infections
Infections may trigger the formation of ANCA and a fraction of patients with infection-triggered ANCA develop ANCA-associated vasculitis 5. Proposed mechanisms of ANCA formation during the course of infection include:
- Initiation of autoimmune response by microbial peptides that are complementary to autoantigens
- Epigenetic silencing and antigen complementarity leading to upregulation of autoantigen genes
- Molecular mimicry between bacterial and self-antigens
- Formation of neutrophil extracellular traps that stimulate immune processes including production of ANCA
- Interaction of bacterial components with Toll-like receptors, which leads to formation of mediators affecting the immune responses to infections and can trigger ANCA production 5
Pathogenesis of ANCA-Associated Vasculitis
The pathogenesis of ANCA-associated vasculitis involves the activation of neutrophils by ANCA, which release factors that activate the alternative complement pathway, generating C5a, a chemoattractant for neutrophils 4. Activated neutrophils adhere to and penetrate vessel walls, releasing toxic oxygen radicals and destructive enzymes that cause apoptosis and necrosis of the neutrophils as well as of the adjacent vessel wall cells and matrix 4.