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Relationship between ANCA and disease activity in small vessel vasculitis patients with anti-MPO ANCA
J Ara1, E Mirapeix, R Rodriguez
1Servei de Nefrologia, Hospital Clínic, Barcelona, Spain.
Background:
We analysed the usefulness of antineutrophil cytoplasmic antibodies (ANCA) as a marker of clinical activity in patients with small vessel vasculitis associated with anti-myeloperoxidase (MPO) ANCA.
Methods:
We studied a group of 25 patients, 15 with microscopic polyangitis and 10 with renal limited vasculitis, so-called rapidly progressive glomerulonephritis type III. The clinical and serological follow-up was accomplished quarterly over an average of 2.79 +/- 2.08 years (range 0.25-6 years). ANCA was analysed by indirect immunofluorescence and enzyme-linked immunosorbent assays (ELISAs).
Results:
At the time of diagnosis, all patients were ANCA positive (P-ANCA and anti-MPO). Following a standardized treatment, all patients except one achieved complete remission of vasculitis in <3 months. One patient suddenly died during the active phase (1 month of follow-up) and with positive ANCA. Seroconversion from positive to negative occurred in 24/25 patients (96%). Eighteen of these 24 patients (75%) achieved the seroconversion within the first 6 months. During the follow-up, two patients had four major relapses, all of them associated with positive ANCA. ANCA seroconversion from negative to positive was observed in one patient with microscopic polyangitis without clinical relapse of vasculitis.
Conclusion:
ANCA should be used in conjunction with other markers of disease activity in the management of microscopic polyangitis and renal limited vasculitis patients with anti-MPO ANCA.
Insights
Antineutrophil cytoplasmic antibodies (ANCA) are useful markers for monitoring small vessel vasculitis. Most patients with anti-myeloperoxidase (MPO) ANCA achieved remission and seroconversion, with relapses linked to positive ANCA levels.
Area of Science:
- Nephrology
- Immunology
- Rheumatology
Background:
- Small vessel vasculitis (SVV) management requires reliable markers of disease activity.
- Anti-neutrophil cytoplasmic antibodies (ANCA), specifically anti-myeloperoxidase (MPO) ANCA, are implicated in SVV pathogenesis.
Purpose of the Study:
- To evaluate the utility of ANCA as a biomarker for clinical activity in patients with anti-MPO ANCA-associated small vessel vasculitis.
- To correlate ANCA status with disease remission and relapse in microscopic polyangitis and renal-limited vasculitis.
Main Methods:
- Prospective study of 25 patients (15 microscopic polyangitis, 10 renal-limited vasculitis) with anti-MPO ANCA.
- Quarterly clinical and serological follow-up over an average of 2.79 years.
- ANCA analysis using indirect immunofluorescence and ELISAs.
Main Results:
- All patients were ANCA-positive at diagnosis; 96% achieved seroconversion to ANCA-negative within 6 months of treatment, correlating with remission.
- Relapses in two patients were associated with positive ANCA.
- One patient showed ANCA seroconversion from negative to positive without clinical relapse.
Conclusions:
- ANCA monitoring is valuable in managing anti-MPO ANCA-associated microscopic polyangitis and renal-limited vasculitis.
- ANCA status, alongside other markers, aids in assessing disease activity and guiding treatment.
- Seroconversion to ANCA-negative status is a strong indicator of remission.