1. First Department of Paediatrics, National and Kapodistrian University of Athens, ‘Aghia Sophia’ Children’s Hospital, 115 27 Athens, Greece
2. Immunology and Vaccinology Research Lab, First Department of Paediatrics, National and Kapodistrian University of Athens, 115 27 Athens, Greece
3. University Research Institute for the Study of Genetic & Malignant Disorders in Childhood, School of Medicine, National and Kapodistrian University of Athens, ‘Aghia Sophia’ Children’s Hospital, 115 27 Athens, Greece
4. Department of Paediatric Surgery, ‘Aghia Sophia’ Children’s Hospital, 115 27 Athens, Greece
5. Department of Microbiology, Athens Medical School, 115 27 Athens, Greece