From the Guidelines
P-ANCA positivity with elevated myeloperoxidase antibodies is a strong indicator of microscopic polyangiitis (MPA), requiring immediate evaluation by a rheumatologist or nephrologist for definitive diagnosis and treatment. This condition is characterized by vasculitis without granulomatous inflammation, commonly presenting with rapidly progressive pauci-immune glomerulonephritis and alveolar hemorrhage 1. The presence of myeloperoxidase antibodies is a key diagnostic marker for MPA, and treatment should be initiated promptly to prevent organ damage.
Key Considerations
- MPA is a form of ANCA-associated vasculitis that affects small- and medium-sized vessels, leading to multisystem organ involvement 1
- Elevated myeloperoxidase antibodies are a hallmark of MPA, and treatment should be tailored to reduce antibody levels and prevent further organ damage
- Initial therapy often includes high-dose corticosteroids (prednisone 1 mg/kg/day, maximum 60-80 mg daily) combined with an immunosuppressant like cyclophosphamide (1.5-2 mg/kg/day orally) or rituximab (375 mg/m² weekly for 4 weeks) 1
- For severe disease with organ involvement, methylprednisolone pulse therapy (500-1000 mg IV daily for 3 days) may be initiated to rapidly reduce inflammation and prevent further organ damage
Treatment and Management
- Treatment typically involves induction therapy for 3-6 months followed by maintenance therapy with lower-dose steroids and agents like azathioprine, methotrexate, or mycophenolate mofetil 1
- Patients should be monitored regularly for disease activity, medication side effects, and infection risk to ensure optimal treatment outcomes
- Regular follow-up with a rheumatologist or nephrologist is crucial to adjust treatment plans as needed and prevent long-term organ damage 1
From the Research
P-ANCA Positive and Myeloperoxidase Antibodies High
- A person with P-ANCA positive and high myeloperoxidase antibodies may be diagnosed with a form of ANCA-associated vasculitis (AAV) 2, 3.
- The clinical and pathological characteristics of MPO-ANCA positive granulomatosis with polyangiitis (GPA) have been analyzed in several studies, which suggest that this subset of AAV patients has relatively milder renal injury 2.
- MPO-ANCA positive GPA patients are likely to have a distinct phenotype compared to PR3-ANCA positive GPA patients, with less severe organ involvement and a higher prevalence of subglottic stenosis 3.
- Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare condition that can present with positive MPO-P-ANCA, and its diagnosis can be challenging due to atypical presentations 4.
- The spectrum of ANCA-specificities in EGPA includes various target antigens such as MPO, PR3, PTX3, and OLM4, which may segregate further EGPA subgroups 5.
- Myeloperoxidase-ANCA IgG can induce different forms of small vessel vasculitis based on the type of synergistic immune stimuli, including GPA, MPA, and EGPA 6.