1 Rheumatology Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), Athens, Greece. dmaritsi@gmail.com.
2 Infectious Diseases Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), Athens, Greece.
3 Rheumatology Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), and Neurology Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, School of Medicine, National and Kapodistrian University of Athens (NKUA), Athens, Greece.
4 Rheumatology Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), Athens, Greece.
5 Rheumatology Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), and Infectious Diseases Unit, Second Department of Paediatrics, "P. & A. Kyriakou" Children's Hospital, Medical School, National and Kapodistrian University of Athens (NKUA), Athens, Greece.