Immunology and Rheumatology Faculty Reach Across Divisions to Fight Disease

In many ways, modern medicine is getting more intimate in scope: Think targeted cell-based therapies or interventions tailored to the microbiome. But in another sense, its scope is also getting broader: More and more frequently, doctors from various specialties are realizing how important interdisciplinary care is to fight diseases and care for patients. The immunology and rheumatology division is a perfect illustration of this principle. Among others, both Matt Baker, MD, MS, clinical assistant professor of immunology and rheumatology, and Tamiko Katsumoto, MD, clinical assistant professor of immunology and rheumatology, are working collaboratively with other divisions on research and patient care.

Baker “really fell in love with immunology” when he worked in a lab at the National Institutes of Health before attending medical school at Harvard. His path to medicine was unusual: He grew up in a tiny town in Oregon, living in a log house and attending the local high school, where they had classes in “hatchet throwing and log rolling.” He remembers being struck by the role that his father (the town dentist) and the town doctors played. “It was very Rockwellian—seeing them take care of entire families or running down to help when there was an injury at a sporting event,” Baker explains, “so I always had this idea that I would go into medicine.” After internal medicine training, he chose to specialize in rheumatology. “Ten or 20 years ago, many of the other fields within medicine weren't really focused on the immune system,” Baker says. “But now it's clearly involved in just about everything. It was, and is, a really exciting time to be in the field.”

His work eventually led him to Stanford, where he’s become one of the go-to doctors on the West Coast for sarcoidosis, a rare disease that can manifest in various ways, including fibrotic lung disease, lymph node enlargement, and life-threatening problems in the heart. Ron Witteles, MD, associate professor of cardiovascular medicine, often referred his sarcoidosis patients with cardiac involvement to Baker. Soon Baker and Witteles were co-managing close to 20 patients. “There was a need to bring people together around sarcoidosis,” Baker explains. They wanted to “formalize and standardize” their practice.

At first, this included capturing patient information in a database and collecting samples from willing patients to use for future studies. It snowballed from there—cardiac sarcoidosis is a rare form of the disease; it’s more common to see pulmonary problems. So Baker and Witteles started to include pulmonologists (including Rishi Raj, MD, clinical professor of pulmonary and critical care medicine) in their work. From there, it transformed into what is now known as the Stanford Multidisciplinary Sarcoidosis Program, co-directed by Baker, Witteles, and Raj and staffed by Emily Braley, RN. The program began in June 2019, and as the only program of its kind in Northern California, it’s become a hub for sarcoidosis patients.

As part of the program, doctors try to coordinate their clinic days so they can see patients together or at least ensure that the patients can see all the different subspecialists they need to in one day. Baker and his colleagues hope to develop their own algorithm and practice guidelines for the diagnosis and management of sarcoidosis.

Baker is also collecting patient samples to investigate specific cell types that might be involved in sarcoidosis pathogenesis, and he’s recruiting for a study to determine the effectiveness of a drug approved for rheumatoid arthritis in sarcoidosis patients.

The far-reaching ambition of the program is a simple one. “A lot of people come from far away,” Baker says, “so we want to make their visits efficient. Our goal is to be able to provide the best collaborative care possible.”

Katsumoto also preaches the benefits of interdisciplinary work. She always had “a profound love of internal medicine,” and when the time came to choose her specialty, she found herself torn between oncology and immunology and rheumatology. Ultimately she chose immunology and rheumatology, but as she points out, in many ways her career has now come full circle: After years at UC-San Francisco, then Genentech, and now Stanford, her work has resulted in the creation of a new interdisciplinary project: the Immune-Related Toxicity Group.

The idea for this group arose from the growing trend of applying immunology to cancer treatments, and in Katsumoto’s case, the use of checkpoint inhibitors to fight tumors. As Katsumoto explains, “Normally, the immune system is capable of identifying a tumor and mounting a productive response against it. When cancer develops, often the tumor evolves mechanisms of resisting immune attack.” The checkpoint inhibitors administered by doctors then block the resistance mechanism of the tumor, thereby “unleashing the immune system by taking the brakes off” and allowing the immune system to recognize and attack the tumor. Checkpoint inhibitors have generated impressive long-term responses in some patients, but there’s a secondary issue. When you take the brakes off the immune system, it leaves the patient vulnerable to “immune-related adverse events.”

“Sometimes you get collateral damage to your own internal organs,” Katsumoto says. That’s where she and her colleagues in medicine—jokingly referred to as “the cleanup crew”—come in, and how she first got the idea for the group.

Katsumoto realized while treating these adverse events that there were still knowledge gaps, despite the existence of several guidelines. Clinical questions frequently arise, such as how to optimally manage these adverse events, whether it’s safe to restart the checkpoint inhibitor, and whether it’s safe to use checkpoint inhibitors in patients with pre-existing autoimmunity. Katsumoto wondered about creating a working group, akin to a tumor board, that could provide consultative services, a database, and even a biobank for all these adverse events. As Katsumoto puts it, “It became clear that there was a need for us to come together as a larger multidisciplinary group to really discuss these cases and learn from each other.”

The group is still in its infancy, but Katsumoto has identified interested parties from various disciplines (including oncology, dermatology, gastroenterology, pulmonary medicine, endocrinology, nephrology, hepatology, and neurology), and she’s already getting referrals for patients from colleagues. She’s also involved in a large multisite NIH trial seeking to discover whether patients with pre-existing autoimmunity can safely use checkpoint inhibitor therapy. Another major project involves biomarkers: If doctors can discover which biomarkers identify patients who will respond negatively to checkpoint inhibitor therapy, they can identify problems before any therapy is administered.

She’s hoping to convene the group as a resource for doctors in this rapidly changing field. “This could be a springboard for a lot of collaborative research projects,” Katsumoto envisions. She also hopes that identifying “point people” in various divisions can help improve clinical care.

The Immune-Related Toxicity Group is a relatively new idea for Katsumoto, but her goals for the project prove her determination, and her collaborators are just as eager. “The use of checkpoint inhibitor therapy is growing, almost exponentially. More and more medications are getting approved for new indications every day,” Katsumoto says. And that only proves the greater need for collaboration. As Katsumoto asserts, “The field is growing in real time. We need to band together.”