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Prevalence of ANCAs in patients on maintenance haemodialysis
S Weidemann1, S Apenberg, K Andrassy
1Department of Medicine, University of Heidelberg, FRG.
Insights
The prevalence of Wegener's granulomatosis and microscopic polyarteritis is four times higher in German dialysis patients than previously thought. Low ANCA-IF titers without specific antibodies indicate an increased autoimmune tendency, not disease.
Area of Science:
- Nephrology
- Immunology
- Rheumatology
Background:
- Wegener's granulomatosis (WG) and microscopic polyarteritis (MP) incidence varies across Europe, with Germany reporting lower rates.
- Traditional diagnostic methods, often relying on histology, identify only a fraction of affected cases.
- Antineutrophil cytoplasmic antibody (ANCA) serology offers a more accessible diagnostic tool for WG and MP.
Purpose of the Study:
- To investigate the prevalence of ANCA-associated vasculitis in a large cohort of German hemodialysis (HD) patients.
- To evaluate the diagnostic significance of ANCA-IF, PR3-AB, and MPO-AB in this population.
- To determine if low ANCA titers without specific antibodies indicate underlying pathology in HD patients.
Main Methods:
- Concomitant determination of ANCA-indirect immunofluorescence (ANCA-IF), proteinase 3-antibodies (PR3-AB), and myeloperoxidase-antibodies (MPO-AB).
- Analysis of a larger cohort of patients undergoing chronic hemodialysis (HD).
- Comparison of prevalence data with European Dialysis and Transplantation Association (EDTA) registry and international incidence rates.
Main Results:
- The prevalence of WG and MP in German HD patients is fourfold higher than previously estimated.
- Low ANCA-IF titers without detectable PR3-AB or MPO-AB are common and suggest an increased autoimmune tendency.
- C-ANCA with PR3-AB is indicative of WG, while p-ANCA with MPO-AB is typical of MP in the German population.
Conclusions:
- ANCA serology is crucial for diagnosing WG and MP, especially in HD patients with undiagnosed renal disease.
- The higher-than-expected prevalence highlights the importance of ANCA screening in German dialysis populations.
- Distinguishing between pathological ANCA findings and general autoimmune tendencies in HD patients is essential for accurate diagnosis.
Abstract:
ANCA analysis as evaluated by concomitant determination of ANCA-IF, PR3-AB and MPO-AB in a larger cohort of dialysis patients disclosed that the prevalence of Wegener's granulomatosis and microscopic polyarteritis in Germany is 4 fold higher than hitherto believed. Low ANCA-IF titers without measurable PR3-AB or MPO-AB are not pathological- they resemble an increased autoimmune tendency of the dialysis patients. According to the european dialysis and transplantation association (EDTA)-registry the incidence of Wegener's granulomatosis (WG) and microscopic polyarteritis (MP) on haemodialysis (HD) in Germany is 0.5% and the prevalence is in the same range (1). In contrast to Germany the incidence in France and Great Britain is above 2%. This is mainly based on histologically proven diseases, which can identify only 1/3 of all affected cases, corresponding to our own experience. With the advent of ANCA serology, WG and MP can be diagnosed more easily. C-ANCA with proteinase 3-antibodies (PR3-AB) is typical of WG, and p-ANCA with myeloperoxidase-antibodies (MPO-AB) is typical of MP in our country. Since a considerable number of patients are on chronic HD without knowledge of their underlying renal disease we studied the prevalence of ANCAs in a larger cohort of HD patients.