New insights into the evolution of serum calprotectin and urinary CD163 in ANCA-associated vasculitis during...

ANCA-associated vasculitis (AAV) is a rare autoimmune disease that causes inflammation of small blood vessels, often leading to organ damage, particularly in the kidneys. Biomarkers like calprotectin and CD163 have been proposed as indicators of disease activity and inflammation. This study aims to analyze the dynamics of calprotectin and usCD163 during stable remission.

This retrospective observational study included AAV patients in remission receiving rituximab as maintenance therapy. Seventeen patients were included, with 78 samples available for analysis. Serum calprotectin and usCD163 levels were measured using ELISA, and clinical data were collected from electronic medical records.

Seventeen AAV patients in remission were analyzed. usCD163 and serum calprotectin levels showed a significant positive correlation (p=0.005). Both biomarkers correlated with CRP, and usCD163 also correlated with ESR. Levels of both biomarkers were higher within 6 months after a disease flare. During follow-up, mean biomarker levels were higher in patients who later relapsed, though only usCD163 reached statistical significance (p=0.05). Calprotectin levels were significantly higher in patients who had received rituximab less than three months prior compared to those treated 9-12 months earlier (p=0.031).

suCD163 and serum calprotectin may serve as biomarkers for disease activity and relapse in AAV. Their correlation with renal function outcomes and higher levels in patients who relapsed suggest that they might be useful to measure persistent immune activity. Further studies are needed to explore their role in predicting flares and guiding personalized treatment strategies.