1. Paediatric Allergy and Immunology, University of Manchester, Manchester
2. UK–PIN UKPID Registry Team, London and Manchester
3. Immunology, Royal Free Hospital, London
4. Immunology, St Bartholomew's Hospital, London
5. West Midlands Immunodeficiency Centre, Birmingham Heartlands Hospital, Birmingham
6. Immunology, Derriford Hospital, Plymouth
7. Immunology, NHS Greater Glasgow and Clyde, Glasgow
8. Immunology, John Radcliffe Hospital, Oxford
9. Department of Immunology, University Hospital of Wales, Cardiff
10. Immunology, Salford Royal Foundation Trust, Manchester
11. Immunology, Addenbrookes Hospital, Cambridge
12. Immunology, Papworth Hospital, Cambridge
13. Regional Immunology Service, the Royal Hospitals, Belfast
14. Department of Immunology, Manchester Royal Infirmary, Manchester
15. Primary Immunodeficiency Group, Newcastle University, Newcastle upon Tyne, UK