For the past 3 decades until 2014 Professor Ress has been head of a general medical team in internal medicine, as well as head of the Division of Clinical Immunology in the Department of Medicine at Groote Schuur Hospital & University of Cape Town (UCT). His activities have included research in TB and autoimmunity, providing an autoimmune routine diagnostic serological service, laboratory evaluation of immune status, and teaching of immunology to under and post-graduate medical students. He is currently an Emeritus Associate Professor of Medicine at UCT where he continues to be involved in research. He also consults as a specialist physician & Clinical Immunologist at the UCT private academic hospital in Observatory, Cape Town. This includes the evaluation of immune function in patients with recurrent infections who are referred for investigation, and seeing patients with autoimmunity. He also has a longstanding interest in the evaluation and management of patients with the chronic fatigue syndrome.