A protein called SOCS4 has been shown to act as a handbrake on the immune system's runaway reaction to flu infection, providing a possible means of minimizing the impact of flu pandemics. Scientists have found that without SOCS4 the immune response to influenza infection is slowed and there is a vast increase in the number of damaging inflammatory molecules in the lungs. This flood of inflammatory molecules, known as a 'cytokine storm', is thought to contribute to flu-related deaths in humans.