Fig. 1: Kinetics of innate and adaptive immune responses to a virus infection, copied from: (25).
In specific, SARS-CoV-2 infection involves the activation of both innate and adaptive immune systems to clear the infection(26). However, the exaggerated proinflammatory cytokines production has been proposed to cause pathologic condition in lungs characterized by occurrence of respiratory distress which could be followed by pulmonary failure with or without multi organ failure(11).
In the same context, marked increase in proinflammatory cytokines and chemokines such as, Il-1β, Il-2, Il-6, Il-8, Il-17 and TNF alpha was also noticed in COVID-19 cases(27). Moreover, elevated levels of neutrophil lymphocyte ratio (NLR) and proinflammatory cytokines and chemokines in COVID-19 patients was correlated with more severe form of the disease and worse prognosis hypothesizing the relation between the inflammatory responses in patients and the immunopathologic nature of the disease(28).
Another study has shown that SARS-CoV-2 patients with severe complications had increased concentrations of inflammatory markers such as high-sensitivity C-reactive protein (Hs-CRP)(29) which is a member of the pentraxin family and an important acute phase protein that plays a fundamental role in both innate and adaptive immune responses (30, 31).