Increased levels of circulating cell-free DNA in COVID-19 patients with respiratory failure
Akihiko Tanaka, Katsuki Wakayama, Y Fukuda, Shin Ohta, Tetsuya Homma, Koichi Ando, Yuji Nishihara, Ryuichi Nakano, Jing Zhao, Yuki Suzuki, Yoji Kyotani, Hisakazu Yano, Kei Kasahara, Kuei‐Pin Chung, Hironori Sagara, Masanori Yoshizumi, Kiichi Nakahira
Abstract
Cell-free DNA (cfDNA) is released from injured cells and aggravates inflammation. Patients with coronavirus disease (COVID-19) often develop pneumonia and respiratory failure, and require oxygen therapy (OT), including mechanical ventilation (MV). It remains unclear whether cfDNA predicts the risk of receiving OT or MV in COVID-19 patients. Therefore, we hypothesized that circulating cfDNA levels could reflect the severity of respiratory failure and determine a therapeutic approach for oxygenation in patients with COVID-19. We analyzed cfDNA levels in serum samples from 95 hospitalized patients with COVID-19 at Showa University Hospital (Tokyo, Japan). cfDNA levels were assessed by measuring the copy numbers of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) using quantitative real-time PCR (qPCR). Both cf-nDNA and cf-mtDNA levels were negatively correlated with adjusted SpO 2 for FiO 2 (SpO 2 /FiO 2 ratio). Elevated cf-nDNA and cf-mtDNA levels were associated with the requirement for OT or MV during patient admission. Multivariate logistic regression analysis revealed that cf-nDNA and cf-mtDNA levels were independent risk factors for OT and MV. These results suggest that both serum cf-nDNA and cf-mtDNA could serve as useful early biomarkers to indicate the necessity of OT or MV in patients with COVID-19.