MPO and microscopic polyangiitis: In the United Kingdom and northern Europe, Proteinase 3 antineutrophil cytoplasmic antibodies (PR3-ANCA) and GPA are more common than myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCAs); however, in southern Europe, Asia, and India, MPO-ANCA sand MPA are more common than PR3-ANCA and GPA [26].