1 Rheumatology Unit, Second Department of Pediatrics, P. & A. Kyriakou Children's Hospital, Athens Medical School, National and Kapodistrian University of Athens, Greece.
2 Rheumatology Unit, Archbishop Makarios III Children's Hospital, Nicosia, Cyprus.
3 Infectious Diseases Unit, Second Department of Pediatrics, P. & A. Kyriakou Children's Hospital, Athens Medical School, National and Kapodistrian University of Athens, Greece.