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 and sporadic tumor that primarily affects children and is caused by the papillomavirus. The estimated prevalence of this condition is approximately 4 cases per 100,000 children and 2 cases per 100,000 adults. Human papillomavirus types 6 and 11, which are commonly associated with genital warts, are the predominant strains implicated in this disease. The most common symptoms include airway obstruction, voice disturbances, and difficulty speaking. These lesions are typically integrated and are rarely observed individually; they sometimes progress toward malignancy. A total of thirty-one laryngeal samples from patients with a positive pathological response to 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. Accompanying the samples was a form containing detailed patient information. After analyzing the presence of the β-globulin gene in the DNA of the samples, specific primers (MY09/11 and GP5+/6+) were employed to detect the presence of human papillomavirus (HPV). Among the 31 samples, 29 were found to contain the HPV genome, with HPV-6 identified in 13 samples and HPV-11 in 16 samples. The phylogenetic tree of isolated HPV viruses was subsequently plotted. Statistical analyses revealed no significant difference in the incidence of HPV viruses 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 levels, and the incidence of RRP. Additionally, the research indicated that RRP lesions predominantly affect pediatric patients, with only a small percentage of adults being affected. Further extensive studies are necessary to elucidate the main risk factors associated with RRP patients.