LTx Patients with Increased Gastroesophageal Reflux Have Increased CD8+Effector T Cells in BAL

Gastroesophageal reflux (GER) and aspiration of gastric contents have been labeled as risk factors for the development of BOS and surgical correction of GER by gastric fundoplication may be associated with increased freedom from BOS. The mechanisms underlying this relationship remains insufficiently elucidated. The aim of our study was to compare differential cell count and T/B cell characteristics of broncho-alveolar lavage (BAL) cells between LTX patients with and without abnormal GER. Methods GER was assessed using 24hrs impedance-pH monitoring, 1 year after LTx. BAL samples were obtained at the same time, cell count was performed and samples were analyzed by means of fluorescence immunophenotyping for the presence of CD8+ & CD4+ cells. Patients were considered to have increased GER if they had either an increased total number of reflux events (n>75), increased esophageal acid exposure (>5.0%) or increased bolus exposure (>2.0%). Results 52 patients were recruited (40 SSLTx, 11 SLTx, 1 HLTx, 52% female; mean (±SD) age 50.4 ± 12.1 years). 36% (19/52) of LTx patients had increased reflux. BAL characteristics of patients with and without GER are listed in the Table. Patients with increased GER had elevated levels of CD8+ cells as compared to patients with normal GER [64.2 (56.2-79.0) vs 51.8 (41.3-69.0); p=0.0089]. The ratio CD4+/CD8+ was significantly reduced in patients with increased GER [0.3(0.1-0.4) vs 0.5(0.25-1.1); p=0.0024]. Conclusion Pathological GER is associated with an increased frequency of potentially injurious effector CD8 cells in the BAL of lung transplant recipients.