1. Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, University of Oslo, Rikshospitalet, N-0027 Oslo, Norway
2. The Center for Blood Research, Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115
3. Laboratory for Electron Microscopy, Institute of Pathology, University of Oslo, Rikshospitalet, N-0027 Oslo, Norway