Cardiovascular risk in ANCA-associated vasculitis: Monocyte phenotyping reveals distinctive signatures between serological subsets

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) is associated with an increased cardiovascular risk, particularly the myeloperoxidase AAV serotype (MPO-AAV). Distinct alterations in monocyte phenotypes may cause accelerated atherosclerotic disease in AAV. A cohort including 43 AAV patients and 19 healthy controls was included for downstream analyses. Extensive phenotyping of monocytes and monocyte-derived macrophages was performed using bulk RNA-sequencing and flow cytometry. An in vitro transendothelial migration assay reflecting intrinsic adhesive and migratory capacities of monocytes was employed. Subsequent sub-analyses were performed to investigate differences between serological subtypes. Monocyte subset analysis showed increased classical monocytes during active disease, whereas non-classical monocytes were decreased compared to healthy controls (HC). RNA-sequencing revealed upregulation of distinct inflammatory pathways and lipid metabolism-related markers in monocytes of active AAV patients. No differences were detected in the intrinsic monocyte adhesion and migration capacity. Compared to proteinase-3(PR3)-AAV, monocytes of MPO-AAV patients in remission expressed genes related to inflammation, coagulation, platelet-binding and interferon signalling, whereas the expression of chemokine receptors indicative of acute inflammation and monocyte extravasation (i.e., CCR2 and CCR5) was increased in monocytes of PR3-AAV patients. During active disease, PR3-AAV was linked with elevated serum CRP and increased platelet counts compared to MPO-AAV. These findings highlight changes in monocyte subset composition and activation, but not in the intrinsic migration capacity of AAV monocytes. MPO-AAV monocytes are associated with sustained upregulation of inflammatory genes, whereas PR3-AAV monocytes exhibit chemokine receptor upregulation. These molecular changes may play a role in elevating cardiovascular risk as well as in the underlying pathophysiology of AAV. [Display omitted] •Monocytes are activated during active ANCA-associated vasculitis (AAV) and upregulate lipid metabolism-related markers.•AAV monocytes have a normal intrinsic adhesion and migration capacity although net migration likely rises by other mechanisms.•The two serological subsets MPO-AAV and PR3-AAV exhibit differences in monocyte activation and chemokine receptor expression.