1. Department of Biomedicine, University of Pisa, Pisa
2. Institute of ‘Clinica Medica’, University of Bari, Bari
3. Institute of Virology, University ‘La Sapienza’, Rome
4. Chair of ‘Internal Medicine’, University of Milan, Monza
5. Institute of Infectious Diseases, University of Bari, Bari
6. Institute of ‘Clinica Medica II’, University of Padua, Padua, Italy