Dr Petros Karayiannis became a Patron of the Leukaemia Society in 1999 and has worked tirelessly to support the Society through public awareness work. His support has proved an important factor in the Society's efforts to recruit bone marrow donors.

Dr Karayiannis obtained his Batchelor of Science (BSc) Degree in Medical Microbiology from the University of Liverpool, where he continued studying for a Doctorate (PhD) in the same subject. Other professional qualifications include Fellowships of the institute of Biomedical Sciences (FIBMS) and the Royal college of Pathologists. (FRCPath).

His current position is Reader in Molecular Virology at Imperial College, Faculty of Medicine, St. Mary's being one of the constituent campuses where he is based. He is Deputy Editor for the Journal of Viral Hepatitis, member of other editorial boards and past President of the Hellenic Medical Society.