Human Papillomavirus (HPV) Genotype Distribution in Patients with Recurrent Respiratory Papillomatosis (RRP) in Iran

Background: Currently, recurrent respiratory papillomatosis (RRP), common laryngeal warts in the upper airway systems of children and adults are on the increase. Human papillomaviruses (HPVs) are suspected as causative agents. This study concerned HPV incidence and genotype distribution in Iranian RRP patients. Methods: Specimens were collected from RRP patients referred to hospitals affiliated with Iran University of Medical Sciences, Tehran, Iran, from Dec 2014 to Feb 2016 in a cross sectional study. After DNA extraction with an QIAamp® DNA FFPE Tissue Kit, conventional PCR was performed and products were sequenced. INNO-LiPA HPV Genotyping Extra assays as another method for genotyping were conducted. CLC Main Workbench 5 and MEGA6 software as well as SPSS v.20 were used for further analysis. Results: Of the total of 12 patients, 6 (50%) were male. Total mean age (y) ± SD was 9.8±6.3. All RRP patients suffered from HPV infection, with HPV-6 found in 75% (9/12) and HPV-11 in 16.7% (2/12) and one co-infection by both HPV-6 and 11. Statistically, there were no correlations between demographic variables and HPV infection. Conclusion: The major cause of RRP is HPV genotypes 6 and 11 increasing the risk of a requirement for medical interventions. Broader studies are needed to clarify the major risk factors in RRP patients.