The Immunology Department was originally sited in Mercer's Hospital (now ceased function) providing a diagnostic service to the Federated Voluntary Hospitals and St. James's Hospital. In those early days, Tom Scott, Alex Whelan and Brian Dowling initiated the service. In the 1970s, the department moved to the School of Pathology building in Trinity College Dublin. The number of technical staff increased and Dr. John Greally was appointed medical director. At this juncture, the department became actively involved in research. In 1980, Immunology moved again, this time to the St. James's Hospital campus. In 1982, Professor Conleth Feighery was appointed as Consultant Immunologist and Head of the Discipline of Immunology and in 2004, Dr. John Jackson was appointed Chief Medical Scientist of the Diagnostic Laboratories. Over the years, the ever-growing clinical and diagnostic services provided a basis for an expanding programme of research and training of undergraduate and postgraduate students and in 2008, Prof. Derek Doherty was appointed as a third academic in the department. After the retirements of Prof. Feighery and Dr. Jackson in 2012, Prof. Doherty took over the role of Head of the Discipline of Immunology, while Dr. Niall Conlon was appointed as Consultant Immunologist and Head of the Clinical Immunology Service and Dr. Jean Dunne became the Chief Medical Scientist of the Diagnostic Laboratories. In 2015, Prof. David Edgar was appointed as a second Consultant Immunologist and meanwhile, Prof. Feighery continues to contribute to teaching and research as Fellow Emeritus of Trinity College. In 2023, Dr. Dunne took up a research position as Clinical Senior Lecturer and handed over the role of Chief Medical Scientist to Dr. Elizabeth Groarke.