SPEAKER: The immune system is like an orchestra with hundreds of cells and proteins playing their part. But when one section starts to play too loudly, or another section stops playing completely, the whole performance can fall apart. That's sort of what happens with psoriatic disease, says Dr. Elain Husni, a rheumatologist at Cleveland Clinic in Cleveland, Ohio.

ELAINE HUSNI: Your immune system is overproducing. It's revved up. For some reason, it gets triggered and it starts thinking that whatever is part of your body is actually foreign. And it starts to attack it.

SPEAKER: Doctors have been trying to treat psoriatic diseases for thousands of years. For most of that time, progress was slow going. When Husni started practicing 20 years ago, she had one drug to offer her psoriasis patients, Methotrexate. It works by slowing the growth of skin cells, which can divide so rapidly they build up into those signature red scaly patches. But more recently--

ELAINE HUSNI: So there's been an explosion of treatment for many of these immune-mediated diseases. And the reason for this explosion is that we have a better understanding of some of the drivers of the disease process.

SPEAKER: In people with psoriatic disease, the T-helper lymphocytes, an important type of white blood cell, become overactive. They overproduce certain types of proteins called cytokines. It's these excess proteins that start to attack the skin, joints, and other organs. Doctors can intervene with drugs designed to block parts of the immune response and overreaction before they can wreak havoc on your body.

These treatments include TNF inhibitors, IL-17 inhibitors, JAK/STAT blockades, and IL-23 inhibitors. Like a good conductor, these drugs, along with steroids, painkillers, and topical treatments, can stop the symbols clashing. On these blockers--

ELAINE HUSNI: The disease becomes much less. It's much more tolerable. And the symptoms, signs and symptoms are much reduced. We can't cure it. Meaning, I can't take it away completely, but I can certainly control it so much better.

SPEAKER: New developments in medical science could transform psoriatic disease treatment again over the next 20 years. Currently, when a patient goes to the clinic with psoriasis symptoms, doctors have to use trial and error to figure out which drug is right for them. But personalized medicine could change that. In the future, doctors may be able to identify biomarkers in a patient's sequence DNA to tell them which treatment they're most likely to respond to.

To make this a reality researchers need more time and money to continue unraveling the mysteries of our immune system. But they also need more patients to help by filling out surveys, volunteering for studies, and enrolling in clinical trials.

ELAINE HUSNI: So there's nobody or nothing that's too small or too little or unimportant.