1 Centre of Immunology, Division of Applied Medical Sciences, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.
2 Medical Research Council Centre for Transplantation, King's College London, King's Health Partners, Guy's Hospital, London, SE1 9RT, UK.
3 Division of Diabetes and Nutritional Sciences, King's College London, Guy's Hospital, London, SE1 9RT, UK.
4 Peter Gorer Department of Immunobiology, King's College London, Guy's Hospital, London, SE1 9RT, UK.
5 Medical Research Council Centre for Transplantation, King's College London, King's Health Partners, Guy's Hospital, London, SE1 9RT, UK. giovanna.lombardi@kcl.ac.uk.