CRP and anti-neutrophil cytoplasmic antibody-associated vasculitis: Renal involvement is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and patients often present with pauci-immune necrotizing crescentic glomerulonephritis.[1] Tubulointerstitial (TI) lesions can also be found in the kidneys in AAV, although their pathogenesis remains to be elucidated.[1–3] Modified C-reactive protein (mCRP) is a tissue and/or cell-based form of the acute phase protein and has been suggested to be a possible antigen in acute tubulointerstitial nephritis (ATIN).