Mapping B-cell Biology Across the Cardiovascular Territories of Giant Cell Arteritis: Towards a New Therapeutic Approach (RituxiMAP GCA)

B cells are a component of the immune system which appear be important in causing all forms of cardiovascular disease. Until now, it has not been possible to directly study these cells in living patients (essential to assess their potential as the target of new treatments). For the first time in any cardiovascular disease, this study will apply cutting edge scanning technology to visualise B cells in the blood vessels of giant cell arteritis (GCA) patients. GCA is a common and potentially deadly disorder of the blood vessels which is caused by abnormalities of the immune system. Current treatments are mainly limited to steroids. Unfortunately, these drugs bring tremendous side effects and so there is an urgent requirement to discover alternatives. Laboratory investigations tell us that B cells are highly present in GCA and so if the proposed scanning technology fails to identify these cells in the blood vessels of participants, then the technology is unlikely to be useful for other cardiovascular diseases. If, however, the study does successfully visualise B cells, this knowledge could pave the way for clinical trials of B cell targeted treatments (already established in other conditions) as steroid alternatives in GCA. This study aims to map the distribution of the radiotracer zirconium-89 labelled rituximab within the blood vessels of patients with newly diagnosed GCA and compare this with two separate control groups without the condition. This will allow us to determine the role of B cells within this condition, and whether patients would benefit from B cell-depleting treatments such as rituximab.