Changes in serum KL-6 levels are associated with the development of chronic lung allograft dysfunction in lung transplant recipients.

Chronic lung allograft dysfunction (CLAD) remains a leading cause of death after lung transplantation. KL-6 is a reliable biomarker for various interstitial lung diseases and levels are increased in lung transplant recipients with versus without bronchiolitis obliterans syndrome. This study investigated whether changes in serum KL-6 levels over time were associated with CLAD. Twenty-one lung transplant recipients had serum KL-6 measured (NANOPIA®) at baseline and after 7 years. Changes in serum KL-6 levels from baseline were determined. Receiver operating characteristic curves and Kaplan-Meier analysis were used to test the predictive value of changes in serum KL-6 over time. The average increase in KL-6 in patients with CLAD was 15% versus a 28% decrease in non-CLAD patients (p = .042). An 11% decrease in serum KL-6 level was determined as the best cut-off value to be associated with the development of CLAD (86% sensitivity, 78% specificity). Kaplan-Meier analysis confirmed the association between this cut-off and the development of CLAD (log rank p = .013). In this small cohort, changes in serum KL-6 over time were associated with the development of CLAD after lung transplantation.