Global cell-free DNA methylation in patients with active tuberculosis and tuberculosis contacts with latent tuberculosis infection

Introduction To investigate whether the methylation of circulating cell-free DNA (cfDNA) differentiates active tuberculosis (TB) from latent TB infection (LTBI). Methods Patients with pulmonary TB, contacts with LTBI, and healthy controls were enrolled (2018-2021). Plasma cfDNA was extracted, and using a 5-methylcytosine (5mC) DNA ELISA kit, the global methylation of cfDNA (5mC-cfDNA) was measured. Results 59 TB, 63 LTBI, 39 healthy controls were included. The 5mC-cfDNA level was higher in TB (6.4 %) than LTBI (4.1 %) and healthy controls (4.9 %) (both p Conclusion The global cfDNA methylation level was higher in TB than contacts without TB and helped differentiate patients with TB from contacts with LTBI.