From friend to foe: when your immune system turns against you and how to turn it back

For most, thoughts about the immune system only occur with the occasional cut, cold or flu, when healing directly depends on the immune system doing its job. And when you’re healthy, the immune system goes unnoticed, acting as the body’s security and defense system. 

A complex system of cells, tissues and organs, the immune system’s sole purpose is to recognize and keep out foreign invaders to prevent infections and diseases in the body.  

“Think of the body like the leftovers in your refrigerator, they’re going to get moldy. Our bodies don’t get moldy because our immune system recognizes many different invaders and cleans them out,” explains Diane Hollenbaugh, Ph.D., senior director, oncology discovery, AbbVie. “It is a complex task because of the different invaders and the different assaults on your body, which means your immune system has to recognize all these attacks, react and remove the threat.”
 

However, the immune system can go haywire, betraying itself. 

“In rheumatoid arthritis, for example, the immune system is over-activated and attacks the body’s own tissue,” says Gillian Kingsbury, senior principal research scientist, immunology early discovery, AbbVie. “This attack causes inflammation in the joints that creates pain and destruction of the joint tissue.” 

In cancer, and under normal circumstances, the immune system recognizes cancerous or mutated cells in the body and responds appropriately. However, as the cancerous cells mutate and grow, they find ways to trick the immune system into ignoring them and eventually hide from the immune system altogether. 

Fiona Harding, Ph.D., research fellow, discovery oncology, AbbVie, explains, “Cancerous cells and tumors can and do stay visible to the immune system, but bring along protective gear and find ways to subvert it allowing cancer to grow in the body.”

The breakdown of the immune system in autoimmune diseases and cancer may create symptoms that affect the body in different ways and to varying degrees, but the keys to treating both are interconnected. 

“Because autoimmunity and cancer can be considered as related, you are trying to either tamp down the immune system or amp it up. In cancer, you’re trying to induce the immune system to recognize the mutated cells and respond against self,” Harding says. “With autoimmunity, humans have too much response from the immune system and need to shut it down or have it regulated to a healthy level.”

“In either scenario, the targets are the same: the regulators of the immune system. But the goal differs: to turn the regulators on or turn them off,” Kingsbury says.

Scientific collaboration brings hope for patients and the future of treating these diseases.

“We have strong expertise in both immunology and oncology, and we work together to identify where there is overlap and what it means,” Hollenbaugh adds. “But the most important thing is that there is so much potential to benefit here for patients and that’s what it’s all about. The absolute potential for the patients is at the root of all of this.”