1. The Coagulation Laboratory, Medical Department A, Research Institute for Internal Medicine, University of Oslo, Rikshospitalet, Oslo, Norway
2. The Institute for Immunology and Rheumatology, University of Oslo, Rikshospitalet, Oslo, Norway
3. The Department of Pediatrics, University of Oslo, Rikshospitalet, Oslo, Norway
4. The Electron Microscopic Laboratory, Department of Pathology, University of Oslo, Rikshospitalet, Oslo, Norway