AKT1 and bronchiolitis obliterans syndrome: In this study we used serum-withdrawal as the apoptotic stimulus, whilst this is a widely used method of examining the putative effects of stimuli and the anti-apoptotic effects of acid in BO have been characterised in serum-starvation experiments [23,43,44], it will be important to establish if leptin and/or acid induced Akt activation has anti-apoptotic actions against other stimuli, such as chemotherapeutic and chemopreventative agents.