Human papillomavirus infection status of single cells isolated from cervical cytology specimens by simple manual microdissection.

Human papillomavirus (HPV) testing with cytology triage for cervical cancer screening has proven to be useful. It is considered that a significant percentage of HPV-positive women followed by reflex cytology have had multiple-type HPV infections rather than single-type infections. However, the effects of multiple-type infections on changes in the cytomorphology of exfoliated cervical cells have not been investigated. The aim of this study was to validate simple manual microdissection (MMD) maneuver and investigate the HPV infection status of single cells isolated from Papanicolaou (Pap) smears prepared from women with multiple-type infections. Using cytology samples from 90 patients with abnormal Pap smear results, we evaluated the efficiency of the MMD procedure and determined the HPV infection status of single squamous intraepithelial lesion (SIL) cells microdissected from patients with multiple-type infection. When validating the MMD procedure, the HPV-positive rate was 81.5% using 119 MMD samples from the Pap smear in 61 cases with single-type infection. This MMD procedure was able to efficiently collect single cells. Of 119 MMD samples from 29 cases with multiple-type infection, the HPV-positive rate was 42.9%, and most (96.1%) MMD samples exhibited only one genotype. Our MMD maneuver successfully identified HPV genotypes using single cells isolated from cytology specimens. A majority of single SIL cells prepared from multiple-type infection cases turned out to contain only one genotype. In the future, the MMD method could be applied while studying the relationship between the morphological changes exhibited by SIL cells on Pap smear and the infected HPV genotype.