1. Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
2. Department of Neurology, Danish Headache Center, Glostrup Research Institute, Copenhagen University Hospital Rigshospitalet-Glostrup, Glostrup, Denmark
3. Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark
4. Department of Clinical Immunology, Naestved Hospital, Naestved, Denmark
5. Department of Clinical Immunology, Odense University Hospital, Odense, Denmark
6. Department of Clinical Immunology, Aalborg University Hospital, Aalborg, Denmark
7. Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
8. Department of Haematology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark