IL6 and COVID-19: Early work performed to characterize the host immune response of COVID-19 suggested an immune signature consisting of elevated serum cytokines [particularly Interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α], impaired interferon responses, and peripheral lymphopenia as markers of severe disease; other associated inflammatory serum markers include elevated levels of ferritin, lactate dehydrogenase, d-dimer, C-reactive protein, and coagulation factors [36, 37].