Background: Myeloperoxidase (MPO) plays a major role in loss of immunological tolerance leading to tissue destruction in ANCA-associated vasculitis (AAV). Ceruloplasmin is a protein with antiproteinase and antioxidant properties that inhibits MPO activity. Whether serum level of ceruloplasmin at AAV diagnosis has an impact is unknown.

Objectives: The objective of this study was to evaluate the prognostic impact of serum level of ceruloplasmin at diagnosis in patients with granulomatosis with polyangiitis or microscopic polyangiitis.

Methods: We conducted a retrospective unicentric study at Caen University Hospital, involving consecutive adult patients with granulomatosis with polyangiitis or microscopic polyangiitis between 2010 and 2021 who had available serum at diagnosis. Data was collected using the health records.

Ceruloplasmin was measured by standardized nephelometry (normal values: 0.15 – 0.50 g/L). Patients in each subgroup (whole cohort, microscopic polyangiitis and anti-MPO patients) were divided into two groups based on the median serum level of ceruloplasmin.

We estimated survival using the Kaplan-Meier survival curve, and between-group differences were evaluated by the log-rank test. The study was approved by the local ethics committee of Caen University Hospital (n° 1947).

Results: Ninety-two patients were included, 46 (50%) granulomatosis with polyangiitis (41 anti-proteinase 3 and 5 anti-MPO) and 46 (50%) microscopic polyangiitis (45 anti-MPO and 1 anti-proteinase 3). The median level of ceruloplasmin was 0.44 g/L. No significant differences in the clinical presentation were observed between patients in the two groups (p>0.05). We observed 9 (19.6%) deaths in the low ceruloplasmin group and 5 (10.9%) in the high ceruloplasmin group (p=0.39). Vasculitis relapse occurred in 10/46 patients (22%) and 11/46 patients (24%) (p=1), renal failure leading to dialysis and/or renal transplant in 6/46 patients (13%) and 8/46 patients (17%) (p=0.77), respectively. No significant difference in survival was found (p=0.07). The same analyses were performed between the low and the high ceruloplasmin group with the microscopic polyangiitis subgroup (n=46), and no significant differences were found (p>0.05). However, within the anti-MPO subgroup (n=50), the survival was worse in the low ceruloplasmin group (p=0.03).

Conclusion: In anti-MPO AAV patients, serum level of ceruloplasmin at diagnosis seems to be associated with a significant impact on survival.

REFERENCES:

[1]Baskin E, et al. Ceruloplasmin levels in antineutrophil cytoplasmic antibody-positive patients. Pediatr Nephrol. 2002;17(11):917–9.

[2]Ara J, et al. Ceruloplasmin in small vessel vasculitis. Nephrol Dial Transplant . févr 1999;14(2):515-7.

isclosure of Interests: None declared