227 Development of Lymphoid-Like Stroma in Chronic Lung Allograft Dysfunction after Lung Transplantation

and 10.8-fold in average respectively in allograft-implanted lungs compared to isograft-implanted lungs at day 14 after IPTT. At day 28, control allografts showed near-complete obliteration while anti-CCL21 Ab treated allografts had significantly attenuated lumen obliteration (95.9 2.6% (mean SEM) vs. 73.6 3.9%, n 5, p 0.05). Immunohistochemically, T-cell and B-cell zones in lymphoid neogenesis were organized in control allografts, but disorganized in allografts treated by anti-CCL21 Ab. Disorganization of lymphoid neogenesis in the T cell zone was also observed in plt mice after allograft IPTT and graft obliteration was significantly attenuated by day 28 compared with control allografts (66.6 15.2%, n 3, p 0.05). Conclusions: Ab-mediated blockade or genetic deletion of CCL21 attenuates graft obliteration and induces disorganization of lymphoid neogenesis. CCL21 plays an important role in the formation of lymphoid-like stroma and contributes to lymphoid neogenesis, which is associated with chronic graft dysfunction after lung transplantation.