1. Department of Psychosomatics/Psychotherapy and Department of Psychiatry II; University of Ulm; Ludwig-Heilmeyer-Strasse 2 D-89312 Günzburg Germany
2. Institute for Immunology, Federal Research Center for Virus Diseases of Animals; Paul-Ehrlich-Strasse 28 D-72076 Tübingen Germany
3. Institute of Medical Virology, University of Zürich; Gloriastrasse 30 CH-8028 Zürich Switzerland