MPO and microscopic polyangiitis: The diagnosis of GPA as opposed to microscopic polyangiitis is associated with a lower probability of achieving complete remission—defined as no evidence of clinical disease activity while not receiving glucocorticoid treatment2—and a higher risk of relapse.3,4 Similarly, PR3-ANCA positivity as opposed to myeloperoxidase (MPO)-ANCA positivity is independently associated with a higher risk of relapse.3,4