Disturbed patterns of immunocompetent cells in usual-type vulvar intraepithelial neoplasia

Genital infection with human papillomavirus (HPV) is usually transient, as the immune system is capable of eliminating the virus. When immunity "fails" and the infection persists, vulvar intraepithelial neoplasia (VIN) may develop. In this study, we examined the distribution of inflammatory cells in 51 patients with HPV-associated usual-type VIN and in 19 healthy controls. Frozen vulvar tissue samples were tested for the presence of HPV-DNA, and immunohistochemical staining for the markers CD1a, CD207, CD208, CD123/CD11c, CD94, CD4, CD8, and CD25/HLA-DR was performed. Cells were counted in both the epidermis and dermis over at least 2 mm of basal membrane length. In the epidermis of VIN patients, CD1a(+) and CD207(+) (Langerin) dendritic cells (DC) and CD8(+) T cells were significantly lower than in controls, whereas the number of CD123(+)/CD11c(-) plasmacytoid DCs (pDC) was significantly increased. No significant changes were observed for CD208(+) DCs, CD94(+) natural killer (NK) cells, CD4(+) T cells, and CD25(+)/HLA-DR(+) regulatory T cells. In the dermis of VIN patients, elevated numbers of CD208(+), CD123(+)/CD11c(-), CD94(+), CD4(+), CD8(+), and CD25(+)/HLA-DR(+) cells were observed when compared with healthy controls. The numbers of CD1a(+) and CD207(+) DCs were not different between groups. In summary, high-risk HPV-related usual-type VIN lesions are characterized by an immunosuppressive state in the epidermis, showing a reduction of immature myeloid DCs (mDC) and CD8(+) T cells. In the dermis, inflammatory activation is reflected by the influx of mature mDCs and pDCs, NK cells, and T cells, suggesting that the cellular immune response on viral HPV infection occurs in the dermis of VIN patients.