Figure 7. Banff Lesion Score ptc (peritubular capillaritis). Peritubular capillaritis is a form of MVI and a feature of AMR activity and/or antibody interaction with tissue. Each image demonstrates the various ptc Scores which are in themselves determined by the number of inflammatory cells present within capillary lumina. A, Banff Lesion Score ptc1—Mild peritubular capillaritis defined as at least 1 cell in ≥10% of cortical PTCs (short arrows) with 3 to 4 in the most severely involved PTC (long arrow). Please note the slightly distended, open appearance of the capillary which can be a helpful feature; PAS, original magnification x400. B, Banff Lesion Score ptc2—Moderate peritubular capillaritis defined as at least 1 cell in ≥10% of cortical PTCs (short arrows) with 5-10 in most severely involved PTC (long arrow); PAS, original magnification x400. C, Banff Lesion Score ptc3—severe peritubular capillaritis defined as at least 1 cell in ≥10% of cortical PTCs (short arrows) with >10 in most severely involved PTC (long arrow). PAS, original magnification x400. D, this peritubular capillary is cut longitudinally (short arrow) and although containing 4 mononuclear cells is to be disregarded for scoring. However, the neighbouring peritubular capillary (long arrow) is cut orthogonally and would qualify for Banff Lesion Score ptc1 provided that at least 10% of all PTCs contain at least 1 leukocyte. PAS, original magnification x400.