Genotyping of human papillomaviruses in patients with Recurrent Respiratory Papillomatosis in Firouzgar Hospital, Tehran, Iran.

Recurrent Respiratory Papillomatosis (also known as Laryngeal Papillomatosis) is a benign, sporadic tumor primarily affecting children, caused by the papillomavirus. The estimated prevalence of this condition is approximately four cases per 100,000 children and two cases per 100,000 adults. Human papillomavirus types 6 and 11, commonly associated with genital warts, are the predominant strains implicated in the disease. The most common symptoms include airway obstruction, voice disturbances, and difficulty speaking. These lesions are typically integrated and rarely appear in isolation; in rare cases, they may progress toward malignancy. A total of thirty-one laryngeal samples from patients with a positive pathological diagnosis of recurrent respiratory papillomatosis (RRP) were collected from the hospital's Ear, Nose, and Throat department. Each sample was preserved in formaldehyde and embedded in paraffin blocks. A form containing detailed patient information accompanied the samples. After confirming the presence of the β-globulin gene in the DNA of the samples, specific primers (MY09/11 and GP5+/6+) were employed to detect human papillomavirus (HPV). Among the 31 samples, 29 contained the HPV genome, with HPV-6 identified in 13 samples and HPV-11 in 16 samples. The phylogenetic tree of the isolated HPV strains was subsequently plotted. Statistical analyses revealed no significant difference in the incidence of HPV between men and women, nor in the incidence of RRP. However, a significant correlation was identified between residing in suburban areas, low income, and welfare status, and the incidence of RRP. Additionally, the research indicated that RRP lesions predominantly affect pediatric patients, with only a small proportion of adults affected. Further extensive studies are necessary to elucidate the main risk factors associated with RRP patients.