1. Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
2. Institute of Medical Virology, Charité University Medicine, Berlin, Germany
3. Labor Berlin, Charité-Vivantes GmbH, Berlin, Germany
4. Corelab Immunology, Viollier AG, Allschwill, Switzerland
5. Department of Internal Medicine/Nephrology, Spital Lachen, Lachen, Switzerland