Ramnik Xavier is a core institute member of the Broad Institute of MIT and Harvard, director of the Broad’s Immunology Program, and co-director of the Broad’s Infectious Disease and Microbiome Program. He is the Kurt Isselbacher Professor of Medicine at Harvard Medical School; director of the Center for Computational and Integrative Biology and member of the Department of Molecular Biology at Massachusetts General Hospital (MGH); and co-director of the Center for Microbiome Informatics and Therapeutics at MIT.

As a clinical gastroenterologist and molecular biologist, Xavier studies the specific molecular mechanisms involved in innate and adaptive immunity as well as the genetic variants associated with Crohn’s disease, ulcerative colitis, and autoimmunity. By determining the physiological functions of inflammatory bowel disease-associated polymorphisms, his work illuminates processes underlying mucosal homeostasis and inflammation. Using human cohorts, the laboratory interrogates the microbiome’s impact on immunity and inflammation. Recent studies demonstrated that microbiome variability influences cytokine production and associated microbiome variation with autoimmunity risk, pinpointing microbial structures likely mediating susceptibility. Through a transformative collaboration with the Broad’s Chemical Biology and Therapeutic Sciences Program, the laboratory aims to discover small molecules that can correct pathways defective in Crohn’s disease and autoimmunity.