Since 2025 he is again Scientific Director of the Center for Chronic Immunodeficiency (CCI), Medical Center – University of Freiburg. From 2021 to 2022 he was on sabbatical at the University of California San Diego (UCSD), USA. Since 2019, he is Vice Director of the Institute for Immunodeficiency (IFI) at the CCI. Prior to his current position, he held the position of Scientific Director and Consultant at the CCI from 2011 to 2019. From 2006 to 2011, he was Consultant and Head of the EU Marie Curie Research Group in the Department of Immunology at the Royal Free Hospital, University College London, UK. He habilitated in Internal Medicine at the University of Freiburg in 2006 under the supervision of Prof. Dr. Hans-Hartmut Peter. From 2000 to 2006, he worked as a physician in the Department of Rheumatology and Clinical Immunology at the Medical Center – University of Freiburg. Earlier in his career, he spent three years as a postdoctoral fellow at the National Human Genome Research Institute (NIH) in Bethesda, Maryland, USA, from 1997 to 2000. His medical career began as an assistant physician in the Department of Rheumatology and Clinical Immunology at the Medical Center – University of Freiburg from 1995 to 1997, after completing his medical doctorate at the University of Freiburg in 1995 under the supervision of Prof. Dr. Hermann Eibel. He received his academic training between 1988 and 1995, when he studied medicine in Aachen, Freiburg, and Hamburg.