1. Immunology Area, Pediatric Hospital Bambino Gesù, Viale San Paolo 15, 00146 Rome, Italy
2. Department of Experimental Medicine, Section of Histology, University of Genova, Via G.B. Marsano 10, 16132 Genova, Italy
3. Department of Experimental Medicine, Section of Human Anatomy, University of Genova, Via De Toni 14, 16132 Genova, Italy
4. Immunology Unit, University Hospital of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy
5. Department of Medicine, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy