Appropriate wart treatment method depends on prevalence of HPV type

September 1, 2010

Some skin warts should be treated more aggressively, while others need not be, according to research presented at a poster session at the 26th International Papillomavirus Conference.

Key Points

Montreal - Some skin warts should be treated more aggressively, while others need not be, according to research presented at a poster session at the 26th International Papillomavirus Conference.

"There is not much that is known about the persistence of HPV infections by HPV genotypes associated with skin warts," says Maurits de Koning, Ph.D., a scientist with DDL Diagnostic Laboratory in Voorburg, Netherlands, and the study's principal investigator.

Dr. de Koning notes that it is generally accepted that viral warts are caused by human papillomavirus (HPV), and that in healthy individuals, the HPV-associated warts typically appear on the soles of the feet and the palms of the hands.

The exact positions of the warts were noted, and swabs were taken of the warts, according to Dr. de Koning.

HPV assay

Dr. de Koning published research earlier this year in the Journal of Clinical Microbiology on a new HPV genotyping assay using polymerase chain reaction (PCR) and Luminex xMAP technology. Broad-spectrum PCR permitted amplification of DNA of all known HPV types linked to cutaneous warts. He and co-investigators found that HPV types 1, 2, 27 and 57 were the most prevalent HPV types identified in 89 percent of the warts.

The new assay, which can permit simultaneous identification of 23 HPV types, was used in this analysis.

A total of 231 HPV infections were detected in the 249 warts swabbed at the start of the study. In related research, Dr. de Koning and colleagues found that wart swabs accurately reflected the HPV type that was present in a wart.

The skin area where the warts were located was re-tested after 26 weeks. At that point, 114 warts remained, while 105 had resolved. Even in cases in which the warts resolved, 39 percent (45 of 114) of the HPV types persisted.

The prevalence of HPV 27 was higher, in a statistically significant fashion, in warts that persisted compared to warts that resolved. The prevalence of HPV 4 and HPV 63 were significantly lower.

"The warts that are caused by HPV 27 could perhaps be treated differently than those that are caused by HPV 1," Dr. de Koning says. "Warts that are caused by HPV 1 usually resolve themselves. If we test for these HPV types, the clinician does not have to treat them. If they are caused by HPV 27, they may have to be treated more aggressively."

Immunosuppression

Individuals who are immunosuppressed, such as those who have undergone organ transplants or are infected with HIV, are prone to developing warts on sites that are more visible, such as the face, Dr. de Koning says. Significant physical and psychological morbidity might be the result of confluent plaques of warts present on these cosmetically sensitive area.

"Facial warts are very rare in healthy people," Dr. de Koning says. "It may be that patients undergoing organ transplantation consider using less immunosuppressive drugs because they are getting these warts."

And because patients who are immunosuppressed due to organ transplantation or HIV infection are living longer, the clinical relevance of cutaneous warts rises, according to Dr. de Koning.

"It would be interesting to know which HPV types are causing these warts," he says. "It may a good idea for patients who are undergoing transplantation, for example, to have vaccination prior to transplantation."

In another study of the same cohort of patients, Dr. de Koning and colleagues tested whether cure rates for warts were related to factors such as the site of the wart or the age of the patient.

They found that out of 744 cutaneous warts presenting in 246 patients, 577 were positive for single HPV types, and 118 for multiple types. No HPV virus was detected in 49 warts.

Disclosures: Dr. de Koning is an employee of DDL Diagnostic Laboratory.