Prof. Dr. Klaus Warnatz Senior Physician, Head of Division of Immunodeficieny, Department of Rheumatology and Clinical Immunology Center for Chronic Immunodeficiency (CCI) University Medical Centre Freiburg, Germany Klaus Warnatz completed his degree (1991) as well as his Post Graduate Diploma (Thesis, Dep. of Microbiology) at the University of Aachen, Germany. He started working in 1991 at the department of Internal Medicine, Klinikum Rechts der Isar in Munich, followed by post-doctoral studies at the University of California at San Diego and the University of Freiburg, Germany, where he completed his habilitation in 2006. He specialized in Internal Medicine (2004) and Rheumatology and Clinical Immunology (2006). Since 2006 Klaus Warnatz is Senior Consultant in Rheumatology and Clinical Immunology, from 2008 – 2018 at the Centre of Chronic Immunodeficiency, University Medical Centre Freiburg, overseeing the outpatient clinic for adult immunodeficiency disorders at the CCI and since 2018 Klaus Warnatz is Head of Division of Immunodeficieny at the Department of Rheumatology and Clinical Immunology. His research areas are B cell immunology (main focus on Tbet+ B cells, BCR signaling and differentiation) and etiology, pathogenesis, diagnostics and management of primary and secondary immunodeficiencies in adults (main focus on CVID - Common Variable Immunodeficiency and related disorders, discovery of new forms of immunodeficiency)