Does Therapeutic Plasma Exchange Have A Role in Resistant Cytokine Storm State Of COVID-19 Infection?

In early December 2019, several pneumonia cases of unknown origin were observed in Wuhan (China). A novel enveloped RNA β coronavirus was isolated and named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The new virus rapidly spread across China and worldwide. On March 11th 2020, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic. As of 19June 2020, COVID-19 has been confirmed in 8,385,440 individuals globally with deaths reaching 450,686 with a morality of 5.37%. Egypt has 50,437 confirmed cases and 1938 deaths.

The virus mainly spreads through respiratory droplets from infected patients.The clinical spectrum of COVID-19 infection ranges from asymptomatic forms to severe pneumonia requiring hospitalization and isolation in critical care units with the need of mechanical ventilation due to acute respiratory distress syndrome (ARDS). Main symptoms include fever, fatigue and dry cough. Common laboratory findings include lymphopenia and elevated lactate dehydrogenase levels. Platelet count is usually normal or mildly decreased. C reactive protein (CRP) and erythrocyte sedimentation rate are usually increased while procalcitonin levels are normal and elevation of procalcitonin usually indicates secondary bacterial infection. Ferritin, D-dimer, and creatine kinase elevation is associated with severe disease. Chest computed tomographic scans show a typical pattern of bilateral patchy shadows or ground glass opacity.

Severe COVID-19 conditions are usually due to an aggressive inflammatory response known as "cytokine storm" that is characterized by the release of a large amount of pro-inflammatory cytokines. Lung injury, multiorgan failure, and unfavorable prognosis of severe COVID-19 infection have been attributed mainly to the cytokine storm state.

Many proinflammatory cytokines elevate in COVID-19 patients including IL-1, IL-6, IL-8, IL-10, tumour necrosis factor α (TNF-α) and interferon Ȣ(IFN-Ȣ) stimulating immune cells to invade sites of infection causing endothelial dysfunction, vascular damage, alveolar damage and ARDS. Cytokine storm has been reported in several viral infections including influenza H5N1 virus, influenza H1N1 virus, and the two coronaviruses highly related to COVID-19; "SARS-CoV" and "MERS-CoV".

Therapeutic approaches to manage the COVID-19 cytokine storm might provide an avenue to decrease the COVID-19 associated morbidity and mortality. Options include immunomodulators, cytokine antagonists and cytokine removal. Tocilizumab (IL-6 antagonist), Anakinra (antagonist of IL-1 β), TNF blockers, ruxolitinib (JAK1/2 inhibitor ), corticosteroids, intravenous immunoglobulins and therapeutic plasma exchange (TPE) have been used with variable efficacy.