This review focuses on one particular type of cytokine response, called a “cytokine storm”, which has been associated with three major influenza viruses – the pandemic 1918-19 Spanish H1N1 influenza, H5N1 avian influenza and the pandemic H1N1 influenza of 2009.
An aberrant host immune response (immunopathology) is the main cause of pandemic influenza–related deaths.
As part of the normal host immune response to bacterial and viral infections, cells of the immune system release chemical messengers (cytokines), which control and coordinate host immune responses to invading pathogens.
An unbalanced cytokine response (cytokine storm) can lead to damage of the vascular barrier resulting in tissue edema, capillary leakage, multiple organ failure and death.
There is no singular mechanism when it comes to inducing cytokine storm with respect to pandemic influenza strains.
Inhibition of individual cytokines involved in cytokine storm leads to decreased pathology of influenza infection but also impairs viral clearance.
Treatment options should focus on the overall cytokine imbalance and associated immunopathology rather than using a more targeted approach.