COVID 19 severity is associated with the presence of lung derived cfDNA in plasma

ABSTRACT

Introduction: The presence of cfDNA in the blood is a sign of tissue damage. DNA from lung cells is rarely found in the blood of healthy subjects. We aimed to evaluate lung tissue damage among COVID19 patients and try to find out if the level of cfDNA derived from the lungs might be a predictor of disease severity. Method(s) We recruited hospitalized COVID19 patients and compared them to a control group. The control group included volunteers without current or past diagnosis of Covid19 and no history of pulmonary diseases. Blood samples for cfDNA were taken from all participants. Basic demographic and clinical information were evaluated. Six known methylation patterns typical of pulmonary origin were selected and their levels were measured in each blood sample. Statistical analysis was done to evaluate differences between the levels of cfDNA between COVID19 patients and the control group. Evaluation was done to find correlation between disease severity and cfDNA levels. Result(s) One hundred and eighteen COVID19 patients and 40 volunteers were recruited for the study. Our findings showed a significant difference of cfDNA derived from the lungs between COVID19 patients and the control group (P<0.05). The levels of cfDNA from pulmonary origin were significantly higher among patients with severe disease and were correlated with clinical variables such as mortality, need for respiratory support, chest X Ray severity and hospitalization in intensive care (P<0.05). Conclusion(s) The study demonstrated elevated levels of cfDNA among COVID19 patients. Higher levels were significantly associated with disease severity and mortality.