Written by Professor Niall Conlon, MB BCh BAO, PGDip (Allergy), PhD, MRCP(UK), FRCPath. Consultant Immunologist. Central Pathology Laboratory, St. James’s Hospital, James Street, Dublin 8, Ireland & Dr Daniel Lyons, MB BCh BAO, MRCPI, Registrar Clinical Immunology, St. James’s Hospital, James Street, Dublin 8, Ireland
