What happens when the immune system does not function properly?

The immune system is designed to target and destroy cells, and therefore tightly regulated to limit non-specific killing and collateral damage to the site of injury/infection. Immune system dysfunction can manifest as excessive or insufficient activity. When the immune system is chronically switched “on”, it can cause long-term inflammation and/or auto-immune disorders (where the immune system recognizes normal host cells as foreign and attacks them). Alternatively, if the immune system is chronically weak, it cannot mount an adequate response against pathogens or cancer cells, resulting in a typically “ordinary” disease becoming very serious or even fatal. For related information on immunotherapy please visit our dedicated section in our resource center here.