Association of Serum Calprotectin (S100A8/A9) Level With Disease Relapse in Proteinase 3–Antineutrophil Cytoplasmic Antibody–Associated Vasculitis

Abstract

An increase in serum S100A8/A9 level by month 2 or 6 compared to baseline identifies a subgroup of PR3-ANCA patients treated with RTX who are at higher risk of relapse by 18 months. Since RTX is increasingly used for remission induction in PR3-ANCA-positive patients experiencing a relapse, S100A8/A9 level may assist in identifying those patients requiring more intensive or prolonged treatment.