The host immune responses to SARS-CoV-2 and therapeutic strategies in the treatment of COVID-19 cytokine storm

The ravaging pandemic caused by SAR-CoV-2, a member of β-coronaviruses, marks the end of the year 2019. Despite being identified and classified at the earliest stage, the virus records worldwide soaring transmissibility, morbidity, and mortality. Global data have shown the infection with SARS-CoV-2 to be severe among at least 15% of the infected; the aged and those with premorbid conditions like cancer, cardiovascular, and respiratory diseases. The highest prevalence and mortality are seen in the Americas, with African countries least affected. Severe respiratory distress and multiorgan failure are the usual findings in severe cases. A hyperinflammatory, fulminant, hypercytokinemia that is often further complicated by hypercoagulopathy and multiorgan failure has been reported extensively among severely infected patients. Scientists describe hyper-activated immune response mediated by macrophages secreting copious amounts of interleukin (IL)-6 forming the epicenter of cytokine storm (CS), thereby perpetuating signaling cascade through JAK/Kinase pathway that yields a hypercytokinemia. Researchers globally are exploring JAK/kinase inhibitors, immunomodulatory (immunosuppressive) therapy, cytokines, and cytokine receptor blockers for CS management. In which interestingly some of these agents possess antiviral activity. Here, we reviewed published studies with their respective outcome. However, a lot needs to be done to address the CS of COVID-19 to avert its fatal outcome.