Background Plasma levels of fibrin/fibrinogen degradation products (FDPs) are fibrinolytic marker and rises after any thrombotic event.

Objectives To study whether plasma levels of FDPs could be an indicator of disease status and nephritis complications in antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

Methods Patients with microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA) who were admitted to Showa University Hospital for induction therapy and had their plasma FDP levels checked in the active state from October 2005 to May 2012 were retrospectively included. Plasma FDP levels were compared between the active and inactive states of AAV. Among patients in the active state, plasma FDP levels were evaluated for differences in each disease and were compared between patients with and without nephritis complications. Laboratory markers of AAV and nephritis activity were examined to determine their correlations with plasma FDP levels. Vasculitis disease clinical activity was assessed using Birmingham Vasculitis Activity Scores (BVAS), and the relationship between plasma FDP levels and BVAS is discussed.

Results Thirty-six MPA, 10 GPA, and 4 EGPA patients (34 females and 16 males, aged 73±13) were included. Thirty-two patients were checked plasma FDP levels in both the active and inactive states; fatal cases were not checked in both states. Plasma FDP levels were high in the active state and decreased significantly after therapy (p<0.001). Among patients in the active state, plasma FDP levels were significantly higher in patients with MPA than in patients with GPA (p<0.01); levels were also higher in patients with EGPA, though the difference was not significant. Plasma FDP levels were significantly higher in patients with nephritis than in patients without nephritis (p<0.05). Plasma FDP levels significantly correlated with serum C-reactive protein levels (r_s=0.42, p<0.01), peripheral blood neutrophil counts (r_s=0.57, p<0.001), BVAS (r_s=0.33, p<0.05), plasma D-dimer levels (r_s=0.81, p<0.001), serum creatinine levels (r_s=0.31, p<0.05), estimated glomerular filtration rates(r_s=-0.39, p<0.01), and urinary N-acetyl-beta-D-glucosaminidase (r_s=0.33, p<0.05). No significant correlation was observed between plasma FDP levels and serum antineutrophil cytoplasmic antibody levels. Plasma FDP levels were significantly higher in the patients with proteinuria (p<0.01) and hematuria (p<0.05).

Conclusions Plasma FDP levels are a useful indicator of disease activity and nephritis complications in patients with AAV.

Disclosure of Interest None Declared