Human papillomavirus and pterygium.: Is the virus a risk factor?

Background: Pterygium is a disease of unknown origin and pathogenesis that might be vision threatening. It is characterised by a wing-like conjunctival overgrowth of the cornea. Several studies have investigated human papillomavirus (HPV) as a risk factor for the development of pterygia, but the results are inconclusive. Aim: To investigate a large sample of pterygia for the presence of HPV in order to clarify the putative association between pterygia and HPV. Methods: 100 specimens of pterygium from Danish patients and 20 normal conjunctival biopsy specimens were investigated for the presence of HPV with PCR technique using beta-globin primers to access the quality of the extracted DNA and the HPV primers MY09/11 and GP5+/6+. HPV-positive specimens underwent subsequent HPV typing with type-specific HPV primers and further investigation with DNA in situ hybridisation (ISH). Results: 90 of 100 investigated pterygia proved suitable for HPV analysis by PCR. As b-globin could not be amplified, 10 specimens were excluded from the study. 4 of 90 pterygia harboured HPV. HPV type 6 was identified in all four HPV-positive pterygia. The 20 normal conjunctival biopsy specimens were b-globin positive and HPV negative. All four pterygia that were HPV type 6 positive were DNA ISH negative. Conclusions: The low presence of HPV DNA in pterygia does not support the hypothesis that HPV is involved in the development of pterygia in Denmark.