Graft acceptance depends on donor IL-33 expression in donor.

(A) Relative abundance of eosinophils and T cells as well as eosinophil/T cell ratio in B6 IL-33^−/− vs. wildtype grafts transplanted into CSB-treated Balb/c recipients. (B) Rejection grade of B6 IL-33^−/− vs. wildtype donor grafts transplanted into CSB-treated Balb/c recipients. Top panel shows representative histology (200x, H&E) and bottom panel shows ISHLT A grade. Blue arrows indicate perivascular lymphocytic infiltration. Green arrows indicate obliterative arteritis observed in some B6 IL-33^−/− to Balb/c lung grafts. Lung tissue was collected and analyzed on post-engraftment day 7. Each dot represents a single mouse lung transplant. CSB=co-stimulatory blockade. ns=p>0.05; * =p<0.05; **=p<.01; ****=p<.0001