A Non-Invasive Test for the Diagnosis of Oral Hairy Leukoplakia

1Peking University School and Hospital of Stomatology, Beijing, China, 2Contagious Hospital of Henan Province, Beijing, China

Objective: The purpose of this study was to explore the possibility of diagnosing oral hairy leukoplakia (OHL) by means of a non-invasive test.

Method: Exfoliative cytology and virus DNA specimens were obtained from lesions of 40 HIV sero-positive participants, who demonstrated clinical features of oral hairy leukoplakia. Cytologic smears were processed according to routine Papanicolaou (PAP) stain procedure for detection of morphologic changes and periodic acid-Schiff (PAS) stain procedure for detection of C. albicans hypha invading the parakeratin layer of the epithium under standard microscopy. DNA was extracted from exfoliative cells of OHL lesions, on which real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was used to detect the Epstein-Barr virus (EBV) DNA.

Result: Of the 31 DNA samples, 26 (83.9%) were positive for EBV DNA. 23 (79.3%) of 29 cases demonstrated condensation and margination of nuclear chromatin (nuclear beading), while 19 (65.5%) of 29 cases displayed enlarged binucleation or multinucleation. 18 (62.1%) cases and 24 (82.8%) cases demonstrated either nuclear beading and binucleation or multinucleation. Compared with RT-PCR positive reaction for EBV DNA, the sensitivity of PAP stain used for detection of evidence of virus infection in OHL is 80% (Criteria: either nuclear beading or binucleation or multinucleation was seen). All of the 5 RT-PCR negative for EBV DNA cases were suggested having virus infection by PAP stain. C.albicans hyphe were noted in 83.3% (15/18) cytologic smears.

Conclusion: Noninvasive tests, PAP stain for virus infection morphologic change, PAS stain for C. albicans infection and exfoliative cell RT-PCR positive reaction for EBV DNA are efficient methods to screen for OHL in HIV sero-positive individuals.