1. Department of Clinical Immunology University Hospital Alexandrovska Medical University – Sofia Sofia Bulgaria
2. Clinic of ENT diseases University Hospital Tzaritsa Yoanna –ISUL Medical University ‐Sofia Sofia Bulgaria
3. Department of Dental, Oral and Maxillofacial surgery FDM Medical University‐ Sofia Sofia Bulgaria
4. Department of Genetics Faculty of Biology Sofia University St. Kliment Ohridski Sofia Bulgaria