Figure 5.

Morphologic features of accelerated arteriosclerosis. (A) Artery without preexisting arteriosclerosis, 3 months after TX. Several cells (arrows) interposed between internal elastica and endothelim, with little associated extracellular matrix. Such cells stain positively for α-SMA. Masson trichrome stain (MT), ×550. (B) Artery with prior arteriosclerosis, 3 months after TX. Several cells lying immediately beneath the endothelium. The amount of extracellular matrix they have elaborated is not possible to determine. MT, ×500. (C) Artery at 1 year after TX. The intima is markedly thickened and is quite cellular throughout with abundant relatively mature collagen fibers. MT, ×400. (D) Arteries at 1 year after TX. The left panel shows an artery stained for elastic fibers, showing well-formed layer adjacent to endothelium with prominent cells (arrow) just beneath in the thickened intima. Orcein stain, ×550. Right panel shows artery stained for α-SMA showing hypercellular intima with abundant positivity. Arrow shows the gray-staining internal elastica. Everything within represents expanded intima. Magnification, ×600. (E) Artery at 2 years after TX. The outer portions of the intima are composed of dense collagen, but the inner portion remains hypercellular, although collagen appears to be relatively mature. Patient had active ongoing SAMR. MS, ×350. (F) Artery at 3 years after TX. Distinction between relatively hypercellular inner intimal zone and dense collagen in outer intima remains. Patient had active SAMR. Magnification, ×350 (G) Artery at 3 years. Dense collagenous intima shows only modest cellularity. Patient currently had only minimal evidence of AMR (minimal glomerulitis graded as ± with no PTC infiltration). MT, ×350. (H) Artery in DSA− patient at 55 months. The intima is mildly hypercellular, the elongated cells lying between bands of mature collagen. MT,×350.