Variable Clinical Manifestations of COVID-19: Viral and Human Genomes Talk.

The new coronavirus, known as "SARS-CoV-2"; is the cause of one of the most prevalent infectious viral diseases that was recently announced pandemic by the world health organization. Ongoing research in the fields of prevention, management, and therapy establishes a functional scaffold for clinics during the time of crisis. To obtain this goal, it is necessary that all pathophysiologic aspects of COVID-19 from infection to predisposing backgrounds of infection be identified, so that all the ambiguities of researchers regarding transmission mechanisms, variable clinical manifestation, and therapeutic response can be solved. Here, we firstly discuss about the homology screening between nCoV-2019 and beta-coronavirus family using phylogenetic analyses. Secondly, we analyzed the viral motifs to show that viral entry into the host cells requires a primary activation step performed by FURIN and FURIN-like-mediated enzymatic cleavage on the structural glycoprotein. The cleavage increases viral performance by 1000 folds. We then present a comprehensive view on host cells and the significance of gene variants affecting activation enzymes, supportive entry, and spread mechanisms in humans including renin-angiotensin-aldosterone system (RAAS) a pathway results in certain phenotypes or exacerbate infection-related phenotypes in different organs, hence causes variable clinical manifestations. This is followed by discussing about the importance of personalized medicine in nCoV-2019 exposure. Moreover, chemical drugs prescribed for individuals affected with COVID-19, as well as genes involved in drug transport and metabolisms are reviewed as a prelude to drug response. Finally, we suggest some therapeutic approaches developed based on new methods and technology such as anti-sense therapy and antibodies.