Anti-myeloperoxidase and proteinase 3 antibodies for nephritis flare prediction in anti-neutrophil cytoplasmic antibody-associated vasculitis.

Abstract

The value of myeloperoxidase (MPO) and proteinase 3 (PR3) antibody titres in the assessment of renal disease activity and flare prediction in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is not well known. We performed a retrospective study including 113 AVV patients with renal biopsy-proven pauci-immune necrotizing glomerulonephritis from seven Spanish hospitals. The main inclusion criteria were assessment of MPO antibodies using multiplex flow immunoassay and PR3 antibody measurements using immunoassay chemiluminescence with an identical range of values for all participating centres. Serum MPO antibodies 3 ± 1.2 months before relapse were higher in patients who relapsed [19.2 ± 12.2 versus 3.2 ± 5.1 antibody index (AI); P MPO level monitoring using multiplex flow immunoassay and PR3 measurements using immunoassay chemiluminescence are useful and sensitive tools for the prediction of renal relapse in the follow-up of AAV patients with renal disease and relevant surrogate markers of renal disease activity.