Gene variants and treatment outcomes in antineutrophil cytoplasmic antibody-associated vasculitis

Integrated bioinformatic analysis of the shared molecular mechanisms between ANCA-associated vasculitis and atherosclerosis

BACKGROUND AND OBJECTIVE

Accumulated evidence supports the tendency of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis(AAV) to coexist with atherosclerosis (AS). However, the common etiology of these two diseases remains unclear. This study aims to explore the mechanisms underlying the concurrent occurrence of ANCA and AS.

METHODS

Microarray data of AAV and AS were examined in a comprehensive gene expression database. Weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis (GEO2R) were performed to identify common genes between AAV and AS. Based on the co-expressed genes, functional enrichment analysis, protein-protein interaction (PPI) network analysis, and identification of hub genes (HGs) were conducted. Subsequently, co-expression analysis of HGs was performed, and their expression and diagnostic value were validated. We further explored immune cell infiltration and analyzed the correlation between HGs and infiltrating immune cells. Finally, the reliability of the selected pathways was verified.

RESULTS

The results of the common gene analysis suggest that immune and inflammatory responses may be common features in the pathophysiology of AAV and AS. Through the interaction of different analysis results, we confirmed five HGs (CYBB, FCER1G, TYROBP, IL10RA, CSF1R). The CytoHubba plugin and HG validation demonstrated the reliability of the selected five HGs. Co-expression network analysis revealed that these five HGs could influence monocyte migration. Analysis of immune cell infiltration showed that monocytes in ANCA and M0 macrophages in AS constituted a higher proportion of all infiltrating immune cells, with significant differences in infiltration. We also found significant positive correlations between CYBB, FCER1G, TYROBP, IL10RA, CSF1R, and monocytes/M0 macrophages in AAV, as well as between CYBB, FCER1G, TYROBP, IL10RA, CSF1R, and M0 macrophages in AS.

CONCLUSION

These five HGs can promote monocyte differentiation into macrophages, leading to the concurrent occurrence of AAV and AS. Our study provides insights into the mechanisms underlying the coexistence of AAV and AS.

Lupus nephritis and ANCA-associated vasculitis: towards precision medicine?

Historically the treatment of lupus nephritis (LN) and anti-neutrophil cytoplasmic antibody (ANCA) vasculitis was 'one size fits all'; however, with the emergence of precision medicine initiatives, the field is moving towards more personalized treatment approaches. The recent development of a more accurate and reproducible histopathological classification system for LN could lead to better disease categorization and therefore more targeted therapies. A better understanding of the pathophysiology of LN has provided evidence that not only T but also B cells play an important role, opening new opportunities for individualized treatment approaches. Recent trials have shown calcineurin inhibitors and the anti-CD20 antibodies rituximab and ofatumumab to be effective in the treatment of LN, adding new treatment options. State-of-the-art targeted therapy in ANCA-associated vasculitis (AAV) takes interindividual heterogeneity in disease severity, type of ANCA antibody [myeloperoxidase versus proteinase 3 (PR3)] and the risk for side effects of therapy into consideration. In addition, within an individual, induction therapy differs from maintenance therapy, the same holding true in incident and relapsing disease. Rituximab is now widely used in AAV and it has become clear that prolonged B cell depletion, as in LN, must be achieved to obtain a long-lasting clinical response, especially in anti-PR3-associated disease. Still, despite these advances, molecular and genetic markers are rarely incorporated into diagnostic and treatment algorithms and true precision medicine remains an aspiration that hopefully can be achieved.