Schwensen HF, et al. - Researchers assessed the alteration of Pseudomonas aeruginosa (PA) antibody response in cystic fibrosis (CF) patients following bilateral sequential lung transplantation (LTx). Participants included chronically infected CF patients (n = 20), who had LTx between 2001 and 2016 at Rigshospitalet, Copenhagen. In these patients, a retrospective assessment of PA antibodies and airway bacteriology was performed. PA antibodies showed a significant and continuous decrease post-LTx. The decrease was independent of immediate reinfection post-LTx. Experts noted a similarity between antigenic specificities of the sera post-LTx in each patient and antigenic specificities at the beginning of infection, this suggests a decades long memory of their immune response like an “immunological fingerprint”. A new three-factor explanatory model was introduced.