1. Institute for Transfusion Medicine University Duisburg‐Essen, University Hospital Essen Essen Germany
2. Department of Nephrology University Duisburg‐Essen, University Hospital Essen Essen Germany
3. Department of Infectious Diseases, West German Centre for Infectious Diseases University Duisburg‐Essen, University Hospital Essen Essen Germany
4. Institute of Pathology University Duisburg‐Essen, University Hospital Essen Essen Germany
5. Institute of Pathology University Cologne Cologne Germany