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Abstract: SA-PO936

Clinical Implication of Platelets and Complement C3 as Link Between Innate Immunity and the Coagulation System in ANCA-Associated Renal Vasculitis with Myeloperoxidase (MPO) ANCA Seropositivity

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Baier, Eva, Universitatsmedizin Gottingen Klinik fur Nephrologie und Rheumatologie, Gottingen, Niedersachsen, Germany
  • Tampe, Bjoern, Universitatsmedizin Gottingen Klinik fur Nephrologie und Rheumatologie, Gottingen, Niedersachsen, Germany
Background

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a potentially life-threatening systemic small vessel vasculitis (SVV). It is well established that AAV patients feature an increased risk of developing thrombotic events, and platelets are activated in AAV patients being triggered by the alternative complement pathway. We here aimed to systematically assess the relevance of platelet counts and systemic complement system activation regarding distinct histopathological lesions in ANCA associated renal vasculitis (AARV).

Methods

A total of 53 patients with biopsy proven AARV were retrospectively enrolled in a single center observational study. Multivariate regression analysis was performed to identify parameters associated with platelet counts in AARV compared to disease controls. Finally, the relevance of platelets for disease course and recovery was assessed by survival analysis.

Results

Lower platelet counts correlated with markers of kidney injury including eGFR loss (p=0.0004) and lower complement C3 levels (p=0.0037). Multivariate and subgroup analysis revealed that this association was only present in the MPO ANCA subgroup (eGFR loss: p=0.0009, lower C3: p=0.0032). Lower platelet counts correlated with interstitial fibrosis (p=0.0313), and tubulitis in areas of interstitial fibrosis and tubular atrophy (p=0.0033). Finally, we observed significant differences with increased requirement of kidney replacement therapy or death in the subgroup below median platelet counts (HR: 4.1, 95% CI: 1.6-10, p=0.0047), associated with a prolonged hospitalization in this subgroup (HR: 0.5, 95% CI: 0.3-0.9, p=0.0113).

Conclusion

Based on our observed association between platelets and complement system activation in the MPO ANCA subgroup, we here show an impact on disease course and histopathological lesions implying distinct damage modes in different subtypes of AARV.