Humans’ immune systems are not as different from person to person as previously thought, according to scientists at the Fred Hutchison Cancer Research Center reported Wednesday. The findings, the researchers say, could help pave the way for new drugs or immunotherapies to treat disease and infection in a host of patients, including organ transplant and skin graft recipients.

The crux of the research is the realization that of the tens of millions of T cell receptors that make up what’s known as the adaptive immune system, a small fraction of them are the same. It’s called the variable region of our cells and it may not sound like a big deal but its practical applications are impressive.

“Any significant health problem you could have, your adaptive immune system either is playing a role or should be playing a role,” said Harlan S. Robins, assistant faculty member at the Fred Hutchinson Cancer Research Center and lead author of the study. “I strongly believe at some point this will be one of the most significant ways people fight against disease.”

Think about it this way: When someone gets sick, whether with the flu or cancer, the adaptive immune system kicks in to fight off the sickness. The systems’ responses look the same on a cellular level, regardless of the ailment being fought, meaning that doctors can’t tell from the way the body responds exactly what disease or infection is being killed off. But what if doctors could make a diagnosis based on the way the immune system is responding?

For example, let’s say doctors found 100 people with the same T cell receptor and determined that receptor was involved in fighting off ovarian cancer. In effect, that would create a diagnostic so the next time a patient came in with a sickness their immune system was fighting, doctors could check for that diagnostic and determine whether the patient was fighting off ovarian cancer. With the creation of these diagnostics, doctors could potentially start diagnosing ailments they aren’t able to see yet.

“In principle, your immune cells would make great diagnostics,” said Robins. “However…[they're] fairly useless if everyone’s response, while whopping, is totally different. But since that is not the case…now we open up a whole possibility that set of responses to a particular pathogen is potentially shared between a whole variety of people.”

Or consider this: One week after a burn patient receives a skin graft, his adaptive immune system starts to reject his new, healthy skin. With this new discovery, instead of losing the skin graft, doctors could isolate the subset of cells rejecting the new skin and remove them, thereby allowing the patient to heal with his new skin.

“So many problems are caused by our own immune system, we can dampen that because it’s such a small subset of cells causing problems,” said Robins. “So getting rid of those cells would save us a variety of harm.”

The study is published in the current issue of the journal Science Translational Medicine.