1. Pediatric Rheumatology and Immunology University Children's Hospital Muenster Germany
2. Competence Unit Molecular Diagnostics, Center for Health and Bioresources, Austrian Institute of Technology Vienna Austria
3. Department of Pediatric Hematology‐Oncology, University of Duisburg‐Essen, Essen, Germany, and Department of Applied Health Sciences, University of Applied Sciences Bochum Bochum Germany
4. José Carreras Center for Immunology and Gene Therapy and Internal Medicine I, Saarland University Medical School Homburg Germany