TGF at AAV diagnosis in patients with MPA or those with MPO-ANCA (or P-ANCA) positivity tended to be slightly elevated compared to that in patients with GPA and EGPA or those with MPO-ANCA (or P-ANCA) negativity (p = 0.064 and p = 0.116, respectively). Here, MPO is linked to granulomatosis with polyangiitis.