1. Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
2. Institute for Medical Microbiology, Immunology, and Hygiene, Medical Centre, University of Cologne, Goldenfelsstraße 19-21, 50935 Cologne, Germany
3. Department of Internal Medicine, Evangelisches Krankenhaus, Weyertal, 50931 Cologne, Germany
4. MVZ Dr. Stein + Kollegen, Wallstraße 10, 41061 Moenchengladbach, Germany