Increased clonal hematopoiesis involving DNA damage response genes in patients undergoing lung transplantation

BACKGROUND. Cellular stressors influence the development of clonal hematopoiesis (CH). We hypothesized that environmental, inflammatory, and genotoxic stresses drive the emergence of CH in lung transplant recipients.METHODS. We performed a cross-sectional cohort study of 85 lung transplant recipients to characterize CH prevalence. We evaluated somatic variants using duplex error-corrected sequencing and germline variants using whole exome sequencing. We evaluated CH frequency and burden using chi 2 and Poisson regression, and we evaluated associations with clinical and demographic variables and clinical outcomes using chi 2, logistic regression, and Cox regression. RESULTS. CH in DNA damage response (DDR) genes TP53, PPM1D, and ATM was increased in transplant recipients compared with a control group of older adults (28% versus 0%, adjusted OR [aOR], 12.9 [1.7-100.3], P = 0.0002). Age (OR, 1.13 [1.03-1.25], P = 0.014) and smoking history (OR 4.25 [1.02-17.82], P = 0.048) were associated with DDR CH. Germline variants predisposing to idiopathic pulmonary fibrosis were identified but not associated with CH. DDR CH was associated with increased cytomegalovirus viremia versus patients with no (OR, 7.23 [1.95-26.8], P = 0.018) or non-DDR CH (OR, 7.64 [1.77-32.89], P = 0.024) and mycophenolate discontinuation (aOR, 3.8 [1.3-12.9], P = 0.031).CONCLUSION. CH in DDR genes is prevalent in lung transplant recipients and is associated with posttransplant outcomes including cytomegalovirus activation and mycophenolate intolerance.