MPO-ANCA a useful predictor of ANCA-associated vasculitis relapse
The reemergence of myeloperoxidase-antineutrophil cytoplasmic antibodies — or MPO-ANCA — can serve as a biomarker to predict relapse in patients who achieved remission in MPO-ANCA–positive ANCA-associated vasculitis, according to findings published in Arthritis & Rheumatology.
“Although it has been well documented that patients with [proteinase 3]-ANCA have a higher risk of relapse than those with MPO-ANCA, the usefulness of monitoring ANCA levels to predict disease activities, especially relapse, is controversial,” Haruki Watanabe, MD, of the Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan, and colleagues wrote. “Therefore, it is difficult to draw a firm conclusion about the association between MPO-ANCA transition and relapse from previous studies.”
To analyze the associations between MPO-ANCA levels and relapse in patients with remitted ANCA-associated vasculitis, the researchers evaluated data from two nationwide prospective cohort studies in Japan. The first study enrolled patients with newly-diagnosed ANCA-associated vasculitis from 22 tertiary care facilities between April 2009 and December 2010, while the second study involved 53 tertiary care institutions, from April 2011 to March 2014.
Between the two studies, 477 patients with a diagnosis of ANCA-associated vasculitis were enrolled. All participants also met the criteria for primary systemic vasculitis set by the European Medicines Agency, and had already begun immunosuppressive treatment.
For their analysis, Watanabe and colleagues focused on 271 patients with MPO-ANCA–associated vasculitis who achieved remission by month 6 after beginning induction therapy. They measured MPO-ANCA levels at 0, 3, 6, 12, 18 and 24 months, as well as the time of relapse, which was the primary outcome. The researchers then conducted case-control and multivariate analyses to determine the links between the re-emergence of ANCA and relapse.
According to the researchers, 72% of the 271 participants demonstrated MPO-ANCA levels that decreased to normal range within 6 months of the beginning of treatment. MPO-ANCA then re-appeared in 40% of the 181 patients for which there was complete follow-up data. The re-emergence of MPO-ANCA was more frequent among patients who experienced relapse than in 75 control participants — who had been matched by age and sex — who did not relapse (OR = 26.2; 95% CI, 8.2-101).
“Negative conversion of MPO-ANCA after remission induction therapy was not associated with subsequent relapse and survival, but reappearance of MPO-ANCA after the negative conversion can be a useful biomarker for predicting relapse in remitted patients with MPO-ANCA–associated vasculitis,” Watanabe and colleagues wrote. “This suggests that routine MPO-ANCA monitoring should be implemented in this patient population.” – by Jason Laday
Disclosure: Watanabe reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.