MPO and anti-neutrophil cytoplasmic antibody-associated vasculitis: To determine the cut-off of the novel CytoBead ANCA for PR3- and MPO-ANCA, 465 human sera of patients and controls including 118 patients with ANCA-associated vasculitis, 133 with RA, 49 with ID, 20 with CD, 20 with AIH and 125 BD were run with the Aklides IIF interpretation system.