Fig. 2.

Hyper-cytokinaemic Overlaps Between ARDS and MAS.

Elevated cytokine levels or hypercytokinaemia are associated with the current COVID-19 infection [20] and independently found in the MAS spectrum and many other settings including sepsis [17]. Cytokines including IL-6 may be substantially elevated in isolated ARDS. The magnitude of cytokine level changes may not be reliable in the differentiation from other cause of elevated cytokine levels including severe infection or tissue destruction and dependable cut-off values do not exist. Superimposed second viral or bacterial infections in either setting may further drive systemic cytokine responses. Therefore, phase 3 studies based on elevated IL-6 levels may encompass a group of ARDS cases without the bone fide MAS phenotype [57].