Professor Barbara Fazekas de St Groth is an NHMRC Principal Research Fellow at the Centenary Institute and the University of Sydney Discipline of Dermatology. Her work is aimed at understanding how the immune system is regulated and how the western lifestyle predisposes to immune-mediated diseases such as allergies, autoimmune and inflammatory conditions. Prof Fazekas de St. Groth graduated in medicine with first class honours from the University of Sydney and worked as a Professorial Intern and Resident at Royal Prince Alfred Hospital, Sydney before completing a PhD with JFAP Miller at the Walter and Eliza Hall Institute in Melbourne. She then undertook postdoctoral training with Mark Davis at Stanford University. She returned to Sydney in 1991 to set up her own laboratory at the Centenary Institute, where she was appointed Associate Professor in 2000 and Professor in 2007. She is best known for her work using T cell receptor transgenic mouse models and multiparameter flow cytometry to define fundamental immune processes. More recently she has focused on the role of regulatory T cells in human disease. Together with colleagues at the Centre for Immunology in Sydney, she discovered a novel phenotyping strategy that allows pure populations of human regulatory T cells to be isolated and manipulated for use in the therapy of graft versus host disease and organ graft rejection, in addition to autoimmune disease and allergy. Her current studies use multiparameter flow cytometry to define peripheral blood regulatory T cell subsets in health and disease.