Lesional HPV types of cutaneous warts can be reliably identified by surface swabs

Large numbers of HPV types infect the human skin and members from the HPV genera alpha, gamma and mu are associated with cutaneous warts.

The aim of this study was to test if the HPV genotypes in swabs of the overlying skin are identical to the types present within these warts.

To this purpose, 25 persons being treated for persistent cutaneous warts were enrolled. Swabs of the overlying skin of the wart were collected from each participant. Additionally, scabs of the wart and deeper portions of the warts were surgically removed. HPV genotyping was performed on all samples using the novel HSL-PCR/MPG assay and the HPV genotyping results were compared.

From the 25 wart biopsies one was HPV negative. 15 were positive for HPV27, 3 for HPV57, 2 for HPV2, 2 for HPV1, 1 for HPV3 and 1wart biopsy was positive for both HPV41 and HPV65. Scabs and swabs of the warts both showed identical typing results as the biopsies in 24 of the 25 cases (sensitivity: 96%).

There was an excellent agreement between HPV types in the swabs of the skin that overlies the warts and the biopsies of these warts validating the use of wart swabs for future studies of wart-associated HPV types. HPV27 was highly prevalent (70%) in the in adults of the investigated population of patients with persistent cutaneous warts.