COVID-19: Immunology, Immunopathogenesis and Potential Therapies

Abstract

The Coronavirus Disease-2019 (COVID-19) imposed public health emergency and affected millions of people around the globe. As of January 2021, 100 million confirmed cases of COVID-19 along with more than 2 million deaths were reported worldwide. SARS-CoV-2 infection causes excessive production of pro-inflammatory cytokines thereby leading to the development of “Cytokine Storm Syndrome.” This condition results in uncontrollable inflammation that further imposes multiple-organ-failure eventually leading to death. SARS-CoV-2 induces unrestrained innate immune response and impairs adaptive immune responses thereby causing tissue damage. Thus, understanding the foremost features and evolution of innate and adaptive immunity to SARS-CoV-2 is crucial in anticipating COVID-19 outcomes and in developing effective strategies to control the viral spread. In the present review, we exhaustively discuss the sequential key immunological events that occur during SARS-CoV-2 infection and are involved in the immunopathogenesis of COVID-19. In addition to this, we also highlight various therapeutic options already in use such as immunosuppressive drugs, plasma therapy and intravenous immunoglobulins along with various novel potent therapeutic options that should be considered in managing COVID-19 infection such as traditional medicines and probiotics.

Keywords:

• COVID-19
• cytokine storm
• immunology
• immunotherapy
• SARS-CoV-2

Acknowledgements

AB, LS, CS, ZA, BV, PKM, GCM and RKS acknowledge the Department of Biotechnology, AIIMS, New Delhi, India for providing infrastructural facilities. ZA thanks Dr. Harisingh Gour Central University, Sagar (MP). All figures (except figure 7) are created with the help of https://smart.servier.com/.

Authors’ contributions

RKS contributed in conceptualization and writing of the manuscript. AB, LS, CS, ZA, PKM BV, GCM participated in writing and editing of the review. RKS suggested and AB and LS created the illustrations.

Conflicts of interest

The authors declare no conflicts of interest.

Additional information

Funding

This work was financially supported by projects: DST-SERB (EMR/2016/007158), Govt. of India, Intramural project from All India Institute of Medical Sciences (AIIMS), New Delhi-India and AIIMS-IITD collaborative project sanctioned to RKS. AB thank DST SERB project for research fellowship, LS and ZA thank UGC for research fellowship.