MPO Antibodies Predict Relapses in MPO-ANCA-Associated Vasculitis Save

A study of MPO-ANCA positive patients followed serially over 2 years shows that reappearance of MPO‐ANCA may predict  relapse in patients with MPO‐ANCA positive AAV and that routine MPO‐ANCA monitoring is warranted. 

This study aimed to establish a potential link between myeloperoxidase (MPO)‐antineutrophil cytoplasmic antibody (ANCA) and relapse in those with ANCA‐associated vasculitis (AAV). 

It is generally known that PR3-ANCA is generally associated with granulomatosis with polyangiitis (GPA), MPO-ANCA is regarded as a marker for microscopic polyangiitis (MPA)/renal-limited disease. While both are diagnostically important, their predictive value is less certain.  

From two Japanese cohort studies (477 patients),.271 were  MPO‐ANCA positive and met enrollment criteria. Of these, 183 had microscopic polyangiitis, 34 GPA, 15 with eosinophilic granulomatosis with polyangiitis, and 39 were unclassifiable.

In the vast majority, (72%) MPO‐ANCA levels decreased to normal levels within 6 months of treatment. 

Reappearance of MPO‐ANCA was seen in 73 (40%) of 181 patients with complete follow‐up data. Reappearance of MPO‐ANCA was more frequent in thos with a relapse (odds ratio = 26.2 [8.2–101], P < 0.0001) after adjusting for confounding factors.

Routine MPO‐ANCA monitoring should be implemented in patients with MPO AAV and this may be a useful biomarker for predicting relapse.