Bromodeoxyuridine incorporation and Ki 67 expression in oral hairy leukoplakia.

OBJECTIVES: Oral hairy leukoplakia (HL) is an acanthotic, hyperparakeratotic lesion characterised by the presence of a replicative Epstein-Barr virus (EBV) infection in the superficial and adjoining layers of the epithelium. EBV or its gene products are capable of modifying epithelial differentiation. The aim of this study was to establish whether the presence of EBV was associated with an alteration in cell turnover by assessing bromodeoxyuridine (BrdU) incorporation and Ki 67 expression in lesional tissue and control mucosa. METHODS: Biopsies of HL together with age, site and sex matched controls (n = 7 and 8 respectively) were incubated in 200 microM BrdU in vitro, fixed in methacarn and processed to paraffin wax. Following acid hydrolysis, incorporated BrdU and Ki 67 were identified in serial 5 microns sections using a three-stage immunoperoxidase technique and cell density expressed as the number of positive cells per mm basement membrane length. RESULTS: Overall, there was no difference in the number of BrdU positive cells per mm basement membrane length between control and HL tissue. However, within HL alone, the presence of focal EBV replication was associated with a significant reduction in the number of basal cells incorporating BrdU compared to adjacent EBV free areas (P < 0.05). There was no significant difference between Ki 67 positive cells in control and HL tissue and no evidence of a reduction of Ki 67 positive cells in areas associated with EBV replication. CONCLUSIONS: These results suggest that there is no evidence of a generalised alteration of the proliferative capacity of basal cells in HL, although the focal reduction in BrdU incorporation may reflect subtle changes on cell turnover by EBV infection.

Comparison of cytopathic changes in oral hairy leukoplakia with in situ hybridization for EBV DNA.

OBJECTIVE: It has been observed that the cytopathic changes in hairy leukoplakia (HL) correlate with ultrastructural evidence of intra-keratinocyte herpes-type viral particles. In situ hybridization is considered to be the definitive confirmation of Epstein-Barr virus (EBV)-induced HL. This study evaluated the consistency of histopathological findings, which many believe to be diagnostic, with in situ hybridization for EBV-DNA in 60 patients with lesions clinically suggestive of HL. MATERIALS AND METHODS: Hematoxylin and eosin (H&E)-stained sections were reviewed independently by three oral pathologists who did not know the hybridization results. The presence in keratinocytes of nuclear inclusions and/or homogenization, believed to be specific for EBV in these lesions, was used as an indicator for infection. Cytoplasmic changes were evaluated separately. RESULTS: With in situ hybridization, 48 cases were positive and 12 were negative. When the two methods were compared, pathologist concurrence ranged from 83% to 92%. False negatives ranged from 6% to 19%, and false positives ranged from 8% to 25%. Cytoplasmic ballooning, homogenization, and perinuclear clearing were evident in all cases of hybridization-confirmed HL; however, these changes were also noted in 75% (9/12) of the cases with negative hybridization results. Most confirmed HL cases exhibited both nuclear homogenization and inclusions, although the former was more consistently seen. CONCLUSION: Cytoplasmic changes did not agree well with EBV-DNA hybridization results, whereas nuclear changes demonstrated good, but not complete, agreement. In appropriate clinical settings, the finding of nuclear inclusions and/or homogenization may be of diagnostic value. However, because the potential for false positives and negatives is high, H&E cytopathology should not be used as a substitute for in situ hybridization in the definitive diagnosis of oral hairy leukoplakia.

Diagnosis of Epstein-Barr virus infection in hairy leukoplakia by using nucleic acid hybridization and noninvasive techniques.

The presence of Epstein-Barr virus (EBV) DNA in the epithelial cells of oral hairy leukoplakia is the confirming criterion in the diagnosis of this lesion, which occurs mainly in persons infected by the human immunodeficiency virus. Because hairy leukoplakia often presages the development of the acquired immune deficiency syndrome, it is important that suspicious lesions be accurately diagnosed. Commonly, biopsy tissue is removed for detection of EBV DNA by in situ hybridization, but biopsy is contraindicated in some patients. This study evaluated filter and cytospin in situ hybridization, two noninvasive techniques that examine epithelial cells swabbed from the surfaces of the lesions, for their sensitivity in detecting EBV DNA. As compared with tissue in situ hybridization, the filter and cytospin techniques had sensitivities of 100 and 92%, respectively. We conclude that these two noninvasive techniques can provide the clinician with an accurate alternative to biopsy whenever this human immunodeficiency virus-associated lesion is suspected.

Efficacy of desciclovir in the treatment of Epstein-Barr virus infection in oral hairy leukoplakia.

The efficacy of desciclovir, an analog of acyclovir, in eliminating lesions of oral hairy leukoplakia (HL) and suppressing Epstein-Barr virus (EBV) infection was evaluated in a double-blind, placebo-controlled study of 14 patients. Patients were randomized to receive either the active drug, 250 mg three times a day for 14 days, or placebo. In all eight patients receiving desciclovir, lesions of HL were either completely resolved or significantly reduced during the treatment period, whereas lesions in patients receiving placebo showed no change. The histological features of HL were significantly diminished in patients on desciclovir, and cytochemical, in situ hybridization, and ultrastructural studies showed that EBV infection was eliminated or dramatically reduced in the desciclovir group only. Four patients on desciclovir reported side effects, but none required withdrawal from the study. The reappearance of HL in all eight subjects on desciclovir within 1-4 months after therapy was discontinued suggests the need for additional study.

Oral lesions mimicking hairy leukoplakia: a diagnostic dilemma.

Oral hairy leukoplakia is seen in immunosuppressed persons infected with the human immunodeficiency virus and is a predictor of the development of acquired immunodeficiency syndrome in that population. Over the past 3 years we have seen 16 examples of a lesion that histologically resembles hairy leukoplakia but is found in patients who are not in risk groups for acquired immunodeficiency syndrome. All these specimens tested negative for Epstein-Barr virus DNA and for human papillomavirus antigen. Sera from five of the 16 patients were tested for antibodies to human immunodeficiency virus, and all results were negative. These findings suggest that the diagnosis of hairy leukoplakia cannot be based on histologic criteria alone but should be verified by DNA in situ hybridization for Epstein-Barr virus.

Unusual HPV types in oral warts in association with HIV infection.

Human papillomaviruses (HPV) are associated with certain oral soft tissue lesions, such as papillomas, warts, condylomata, and focal epithelial hyperplasia (FEH). HPV types 2, 6, 11, 16, and 18 have been identified in some of these oral lesions, while HPV 13 and 32 are associated with FEH. Little is known about the HPV types in oral warts of persons infected with human immunodeficiency virus (HIV). In this study, oral warts in 17 HIV-seropositive individuals were biopsied. Southern blot analyses were performed and the HPV types found were HPV 7 (7/17), 13 (1/17), 32 (1/17), and 18 (1/17). The presence of HPV type 7 is unusual in that it normally is found only in butcher's warts. There was no correlation between HPV type, histopathology, and clinical appearance of the lesions examined, except that the flat (FEH type) warts contained HPV types 13, 18 and 32 (1 of each). HIV infection appears to predispose individuals to oral infection with unusual HPV types.