Bavarian Cancer Research Center (BZKF), R/R ALL Study Group, Bavaria, Germany

Maike Breidenbach, Markus Metzler, Marion Subklewe, Fabian Mueller, Paul-Gerhardt Schlegel, Irene Teichert von Lüttichau, Ramona Coffey & Tobias Feuchtinger

Department of Pediatric Hematology, Oncology, Hemostaseology and Stem Cell Transplantation, Dr. Von Hauner Children’s Hospital, University Hospital, LMU Munich, Munich, Germany

Maike Breidenbach, Ramona Coffey & Tobias Feuchtinger

Department of Pediatrics, Division for Stem Cell Transplantation, Immunology and Intensive Care, Goethe University Frankfurt, University Hospital, Frankfurt, Germany

Peter Bader

Department of Pediatric Hematology and Oncology, St. Anna Children’s Hospital, Vienna, Austria

Andishe Attarbaschi & Christina Peters

Department of Pediatric Hematology and Oncology, University Children’s Hospital Muenster, Muenster, Germany

Claudia Rossig

Division of Pediatric Stem Cell Therapy, Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Duesseldorf, Germany

Roland Meisel

Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Erlangen, Germany

Markus Metzler

Department of Medicine III, LMU University Hospital, LMU Munich, Muenchen, Bavaria, Germany

Marion Subklewe

Department of Internal Medicine 5, Hematology and Oncology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria, Germany

Fabian Mueller

Pediatric Hematology and Oncology and Stem Cell Transplantation, University Children’s Hospital Wuerzburg, Würzburg, Germany

Paul-Gerhardt Schlegel

Department of Pediatrics and Children’s Cancer Research Center, TUM School of Medicine, Children’s Hospital Munich Schwabing, Technical University of Munich, Munich, Germany

Irene Teichert von Lüttichau

Department of Oncology and Children’s Research Center, University Children’s Hospital Zurich, Zurich, Switzerland

Jean-Pierre Bourquin

Clinic of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Gabriele Escherich

Department of Pediatrics I, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany

Gunnar Cario

Department of General Pediatrics, Hematology and Oncology, University Children’s Hospital Tübingen, Tübingen, Germany

Peter Lang

Department of Pediatric Oncology and Hematology, Charité Universitaetsmedizin Berlin, Berlin, Germany

Arend von Stackelberg

Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Semjon Willier, Brigitte Strahm & Tobias Feuchtinger

All authors contributed patients’ data and/or were part of the study group. The data merging was done by MB and RC and the retrospective analysis was performed by MB and TF. The manuscript was written by MB and TF and reviewed by all authors.