Akt phosphorylation (Ser-473) was significantly decreased in the atrium of the BO group (Control (n = 6) vs. BO (n = 7): 1.0 ± 0.1 vs. 0.7 ± 0.1 A.U., P < 0.01 vs. Control). Here, AKT1 is linked to bronchiolitis obliterans syndrome.