Compared to MPA-P-ANCA-NS, MPA-P-ANCA-MPO-positive patients had higher prevalence of ANA (63.6%, n = 7/11 vs. 42.9%, n = 3/7) and RF (36.4%, n = 4/11 vs. 14.3%, n = 1/7) and lower prevalence of anti-β2GPI-IgM (0% vs. 14.3%, n = 1/7), anti-Ro52/Ro60 (0% vs. 14.3%, n = 1/7) and anti-TPO (9,1%, n = 1/11 vs. 14.3%, n = 1/7), although these differences did not reach statistical significance (data not shown). The gene discussed is TPO; the disease is microscopic polyangiitis.