Abbreviations ACE2 Angiotensin-converting enzyme 2 APN Aminopeptidase N ARDS Acute respiratory distress syndrome BALF Bronchoalveolar lavage fluid cGAS Cyclic GMP-AMP synthase CoV Coronavirus COVID-19 Coronavirus disease 2019 CSG Coronavirus Study Group DPP4 Dipeptidyl peptidase-4 E protein Envelope protein ECMO Extracorporeal membrane oxygenation ER Endoplasmic reticulum GCSF Granulocyte colony-stimulating factor HGF Hepatocyte growth factor HR1 Heptad repeats 1 HR2 Heptad repeats 2 IFN Interferon IL Interleukin IP-10 10 kD interferon-gamma-induced protein IRF3 Interferon regulatory factor 3 M protein Matrix protein MAVS Mitochondrial antiviral-signalling protein MCP-1 Monocyte chemoattractant protein-1 MCSF Macrophage colony-stimulating factor MDA5 Melanoma differentiation-associated gene 5 MERS-CoV Middle East respiratory syndrome coronavirus MIP-1α Macrophage inflammatory protein 1-α N protein Nucleocapsid protein NF-κB Nuclear factor-κB NSP Non-structure protein ORF Open reading frame PAMP Pathogen-associated molecular pattern PRR Pattern recognition receptor RBD Receptor-binding domain RIG-I Retinoic-acid inducible gene I RTC Replication-transcription complex S protein Spike glycoprotein SARS-CoV Severe acute respiratory syndrome coronavirus STING Stimulator of interferon genes protein TLR Toll-like receptor TMPRSS2 Transmembrane protease serine 2 TNF-α Tumor necrosis factor α TRIF TIR-domain-containing adaptor protein including IFN-β WHCV Wuhan-Hu-1 coronavirus WHO World Health Organization Yan-Rong Guo, Qing-Dong Cao and Zhong-Si Hong contributed equally to this work. Acknowledgements We thank Drs. Hong Shan, Jin-Yu Xia, Zhong-He Li, Jing Liu, Ming-Xing Huang, Xi Liu, Fei Xiao, Shao-Lin Li, Xiao-Feng Li, Xiao-Hua Wang, Xiu-Juan Qu and Ms. Yan Nan from library, from the Fifth Affiliated Hospital, Sun Yat-Sen University, for their sharing the critical information on theranostics of COVID-19 patients and literature searching. Authors’ contributions DYW and YY conceived this review; YRG, QDC, ZH, YYT, SDC, HJJ performed the literature review and wrote the paper; KST, DYW, YY, YRG helped with the review and writing of the paper; all authors read and approved the final manuscript. Funding This study was supported by grants awarded to YY by the National Natural Science Foundation of China (81870019), Guangdong Provincial Natural Science Foundation (2018A030313554), National Key R&D Program of China (2018YFC0910601); DYW by the National Medical Research Council, Singapore (NMRC/CIRG/1458/2016); KST is a recipient of fellowship support from European Allergy and Clinical Immunology (EAACI) Research Fellowship 2019. Availability of data and materials The data and materials used during the current review are all available in this review. Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The funder had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript. The authors declare that they have no competing interests.