“…Human papillomavirus type 6 (HPV-6) and HPV-11 are the predominant HPV viruses that cause papilloma development (21,33), and it is unclear why only a very small faction (4 to 6/100,000) of HPV-6-and HPV-11-exposed individuals develop this disease (4). Furthermore, it is unknown why a still smaller group of individuals has a severe and unrelenting course of disease that can cause significant morbidity, and on occasion mortality, because of the strategic location of papillomas in the airway (2,24). There is clinical variability between patients and, on occasion within a given patient (2,9,24,48).…”