Liquid biopsy as a tool for predicts of severe COVID-19 and hospitalised community-acquired pneumonia.

UNLABELLED

Cell-free DNA (cfDNA) is released into the circulation after apoptosis, necrosis, and active secretion from cells. In a healthy individual, cfDNA is present in small amounts, has a short half-life, and is predominantly derived from circulating hematopoietic cells. The composition and quantity of cfDNA dramatically changes during pathological conditions. Indeed, several studies reported elevated cfDNA concentration as a potential noninvasive biomarker in many diseases.

AIM

The aim of the study was evaluation of the circulating cell-free DNA in patients with severe Covid-19 in comparison with patients with hospitalised community-acquired pneumonia (with and without hyperglycemia and type 2 diabetes mellitus) to determine the specificity, sensitivity and cutoff value of cfDNA for each nosology.

MATERIALS AND METHODS

The studies were carried out on the basis of city and regional hospitals in the Luhansk region between 2015 to 2021. Were examined in the study 28 patients with a positive diagnosis of COVID-19 according to PCR analysis (14 women and 14 men), 60 patients with community- acquired pneumonia (CAP) (30 women and 30 men), 101 patients with community-acquired pneumonia and hyperglicemia (CAP+HH) (44 women and 57 men), 70 patients with type 2 diabetes mellitus (T2DM) (37 women and 33 men), 42 patients with community-acquired pneumonia in combination with type 2 diabetes mellitus (CAP+T2DM) (27 women and 15 men). The control group consisted of 81 healthy volunteer donor (46 women and 35 men). DNA fragmentation was measured with the diphenylamine assay. Statistical and graphical analyses were done using Statistica 7.0 StatSoft software and using GraphPad Prism version 9.0 (GraphPad Software, La Jolla, CA, USA) software.

RESULTS

We found 3-4-fold higher concentration of serum cfDNA levels in COVID-19 patients (womens and mens) compared with healthy controls. Similarly, the levels of cfDNA were 1,5- to 2-fold higher in pneumoniawomens and pneumonia-mens, pneumonia+hyperglycemia-womens and pneumonia+hyperglycemia-mens pneumonia+Type2 Diabetes-womens and pneumonia+Type2 Diabetes-mens, compared with healthy controls. Our results indicate cfDNA profiles on admission can discriminate between patients with COVID-19 and community-acquired pneumonia at risk of severe disease and death with better performance than previously reported inflammatory markers.

CONCLUSIONS

Circulating cell-free nucleic acids (cfDNA) are novel potential biomarkers of COVID-19 and community-acquired pneumonia identified. Our study is one of the first to analyze cfDNA level (the cutoff value of cfDNA concentration) for prediction of COVID-19 and community-acquired pneumonia (with and without complications and comorbidity diseases).