Lipid Profiles in Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis: A Cross-sectional Analysis

Objective. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease (AID) characterised by necrotising intravascular inflammation. Growing evidence suggests that immune system triggers altered lipid metabolism in AIDs. We investigated whether changes in lipid profile correlate with severity of disease in AAV. Methods. Seven lipid profiles were evaluated utilizing frozen serum samples from 67 patients registered in the Severance Hospital ANCA-associated VasculitidEs cohort by a chemistry autoanalyzer. The Birmingham Vasculitis Activity Score (BVAS) version 3 was used to measure patient's assessment of global disease activity. The relationship between the BVAS with continuous variables was calculated by Pearson's correlation analysis. Results. Thirty-five (52.2%), 19 (28.4%), and 13 (19.4%) patients were diagnosed with microscopic polyangiitis, granulomatosis with polyangiitis, and eosinophilic granulomatosis with polyangiitis, respectively. Patients' mean age was 60.0 years, and 22 (32.8%) were male. Among the lipid profiles investigated, total cholesterol, high-density lipoprotein, and low-density lipoprotein, and apolipoprotein A1 and B were significantly associated with BVAS; apolipoprotein A1 showed the highest correlation with BVAS (r=-0.521, p<0.001), remaining consistent even in patients with new-onset disease (r=-0.430, p=0.012). Apolipoprotein A1 had the highest association with the renal manifestation score among the clinical scores comprising BVAS (r=-0.457, p<0.001). Conclusion. Decreased lipid levels, especially apolipoprotein A1, are relevant to increased AAV disease activity, and differ according to organ involvement. Measuring lipid profiles could have clinical implications regarding the assessment of global disease activity and organ involvement patterns.