MPO and anti-neutrophil cytoplasmic antibody-associated vasculitis: Comparing the variables between the two groups, patients with OvSD/pSS/AAV were notably more likely to be ANCA positive (82.9% vs. 1.2%, p < 0.001), MPO-ANCA (or P-ANCA) positive (77.1% vs. 1.2%, p < 0.001), and PR3-ANCA (or C-ANCA) positive (11.4% vs. 0%, p = 0.002) than those without.