Diagnosis Of Oral Hairy Leukoplakia Research Articles

Lingual Lichenoid Lesion Due to Dental Amalgam Fillings: Case Report and Clinical Considerations

Oral white lesions are quite common clinical conditions in clinical dental practice. They can be an expression of different diseases, so it is crucial to achieve a correct diagnosis to start an adequate treatment. However, differential diagnosis is not always easy because the clinical appearance of oral white lesions is often similar and non-pathognomonic. We report on a 42-year-old Caucasian woman who complained of a chronic white patch on the left border of her tongue. A provisional diagnosis of oral hairy leukoplakia was made, but the patient was HIV-negative and not immunocompromised. A patch test was performed to exclude an allergic reaction, which resulted negative. Two large amalgam fillings were removed, and the lesion regressed after two weeks, suggesting a diagnosis of oral lichenoid lesions. Amalgam-associated oral lichenoid lesions could be mistaken for hairy leukoplakia when located on the lateral border of the tongue. Patch tests for dental metal series are only sometimes helpful for a diagnosis of oral lichenoid lesions. Patients should follow a careful follow-up to monitor any neoplastic derailment of the lichenoid lesions.

Oral hairy leukoplakia in an immunocompetent patient treated with topical steroids for oral lichen planus

<h3>Objectives</h3> Oral Hairy Leukoplakia (OHL) is an Epstein-Barr Virus (EBV)-related lesion of the oral mucosa, most commonly affecting immunocompromised patients. Although HIV-infection appears to be the most frequent pre- disposing factor, OHL cases have been reported in patients with other causes of systemic or even local immuno- suppression. Herein, we present a case of OHL arising in an HIV-negative immunocompetent patient treated with topical steroids for Oral Lichen Planus (OLP). <h3>Findings</h3> A 62 years old male patient with biopsy-proven OLP presented for his regular follow-up. He was un- der treatment with topical steroids: fluocinonide (oral gel) and dexamethazone (oral solution). Clinical examina- tion revealed a white plaque of irregular surface involving the right lateral border of the tongue, which had not been noticed in the previous follow up appointment, 2 months ago. With a differential diagnosis of morsicatio linguarum, hypertrophic OLP and leukoplakia, an incisional biopsy was performed. Histopathologic examination revealed hyperkeratotic squamous epithelium with surface corrugations and the presence of "balloon cells" in the upper spinous layer, some of which exhibited nuclear beading in high power magnification. Immunohistochem- ical examination for EBV-LMP1 and in-situ hybridization for EBV were positive, establishing a diagnosis of OHL. Although no symptoms or signs of immunosuppression/HIV infection were present, the patient underwent blood examinations, including an HIV ELISA antibody test, which were within normal limits. In the absence of any in- dications of systemic causes, a diagnosis of OHL associated with local immunosuppression due to long-term use of topical corticosteroids was rendered. <h3>Conclusions</h3> OHL may be associated with different types of immunosuppression. In recent years, few cases of OHL developing in patients treated with topical steroids have been reported, the majority of which were linked to inhalers for pulmonary diseases. Topical steroid-induced immunosuppression in patients with oral mucocutaneous diseases should be considered as a possible, albeit unusual, cause of OHL.

ORAL HAIRY LEUKOPLAKIA IN AN HIV-NEGATIVE PATIENT: CONTRIBUTION OF CYTOPATHOLOGY FOR DIAGNOSIS

Oral hairy leukoplakia (OHL) is an epithelial disorder related to Epstein-Barr virus (EBV) infection generally seen in immunosuppressed patients infected with HIV, with rare cases reported in immunocompetent individuals. A 19-year-old male patient presented a white lesion on the tongue, clinically suggestive of OHL, with burning sensation episodes. The medical history includes a negative test for HIV infection a year ago. The clinical evaluation revealed a white, painless, nonremovable corrugated plaque on left tongue lateral border, evolving within a month. Exfoliative cytology was performed, exhibiting epithelial cells with intracellular edema, nuclei with peripheral chromatin beading, and cells with Cowdry A inclusion bodies and ground-glass pattern. Those findings were compatible with EBV infection that, in conjunction with clinical appearance, led to the diagnosis of OHL. The patient was then submitted to a blood HIV test showing a negative result. The patient is under follow-up of 3 weeks.

Detection of Epstein-Barr virus DNA in saliva of HIV-1-infected individuals with oral hairy leukoplakia.

We present three cases of oral hairy leukoplakia (OHL) in whom the diagnosis was established by EBV DNA detection in whole saliva. Three HIV-infected patients came to the Oral Medicine Clinic with similar chief complaints of asymptomatic white lesions on the tongue. All patients were diagnosed with suspected OHL and oral thrush also in the first patient. A multiplex PCR DNA microarray was performed to detect EBV DNA in saliva collected by spitting method. All saliva samples showed positive results for EBV DNA, and the definitive diagnosis of OHL was made. Resolution of lesions was found at 1- to 2-month follow-up after treatment with application of acyclovir 5% cream 5 times daily. Additionally, anti-fungal treatment was given to the first patient and anti-retroviral treatment to the first and second patients. EBV is mostly transmitted by asymptomatic shedding into saliva. Therefore, the detection of salivary EBV DNA is useful in establishing a definitive diagnosis of OHL allowing more effective treatment for both HIV-infected patients receiving ART and treatment-naïve patients at any CD4+count.

Considerations in the diagnosis of oral hairy leukoplakia—an institutional experience

We report here the 10-year experience with oral hairy leukoplakia (OHL) at the Division of Oral and Maxillofacial Pathology at the University of North Carolina at Chapel Hill, NC, USA. All the associated hematoxylin and eosin and Epstein-Barr virus encoding region in situ hybridization slides of OHL cases between January 1, 2008, and February 1, 2017, were retrieved and reviewed. Collected demographic characteristics, clinical presentation, medical and social histories were reviewed and reported. Six OHL cases with confirmed in situ hybridization showed predilection for the lateral tongue. The study included 3 females and 3 males (mean age 50.5 years; age range 29-70 years). One patient had known HIV-positive status before biopsy was performed. Three patients had reported a history of heavy smoking. Other medical conditions reported were history of breast cancer, a long history of corticosteroid inhaler use for asthma treatment, high cholesterol, diabetes, and hypertension. The findings of this study indicate the need to include OHL as a potential entity in the differential diagnosis of leukoplakic tongue lesions, regardless of the patient's HIV status. In addition, the presence of OHL in the patient requires investigation of various explanations for EBV infection, including immunosuppression caused by HIV infection or chronic steroid use.

Diagnosis of Oral Hairy Leukoplakia: The Importance of EBV In Situ Hybridization.

Oral hairy leukoplakia (OHL) is caused by the Epstein-Barr virus (EBV), which has been related to HIV infection. In situ hybridization (ISH) is the gold-standard diagnosis of OHL, but some authors believe in the possibility of performing the diagnosis based on clinical basis. The aim of this study is diagnose incipient lesions of OHL by EBV ISH of HIV-infected patients and the possible correlations with clinical characteristics of the patients. Ninety-four patients were examined and those presenting with clinical lesions compatible to OHL were submitted to biopsy prior to EBV ISH. Twenty-eight patients had lesions clinically compatible to the diagnosis of OHL, but only 20 lesions were confirmed by EBV ISH. The patients with OHL had a mean age of 41.9 years and were HIV-infected for 11.2 years, on average, including CD4 count of 504.7 cells/mm3 and log10 viral load = 1.1. Among the quantitative variables, there was a statistically significant correlation with age only (P = 0.030). In conclusion, the presence of OHL in patients with HIV/AIDS results in changes in the epidemiological characteristics of the disease, and this fact allied with subtle clinical-morphological features makes clinical diagnosis very difficult. Therefore, EBV ISH is important for a definitive diagnosis of OHL.

Oral lesions as an important marker for HIV progression

Oral hairy leukoplakia (OHL) is a benign lesion caused by Epstein-Barr virus (EBV) replication in the oral epithelium affecting the borders of the tongue. It is strongly associated with immunosuppression, especially in HIV+ adults but is uncommon in pediatric population. The aim of the study is to show the importance of the correct diagnosis of OHL and its influence on HIV treatment.We report two cases of HIV+ adolescent patients that presented with leukoplakic lesions on the border of the tongue, suggestive of OHL. OHL diagnosis was confirmed in only one case through EBV in situ hybridization. After confirmation of the diagnosis, the patient with OHL was referred to an infectious disease specialist with the decision to start antiretroviral therapy. OHL definitive diagnosis can help clinical management of pediatric HIV+ patients.

Oral Hairy Leukoplakia in Patient with Human Immunodeficiency Virus Infection

Oral hairy leukoplakia occurs on the lateral surface of the tongue that clinically as an asymptomatic white lesion. It is mainly found in patient with human immunodeficiency virus infection. However, it rarely outbreak immunosuppressed patients after organ transplantation, or the patients taking steroids or immunosuppressants. It is the result of proliferating Epstein-Barr virus in the oral epithelium. Most of human immunodeficiency virus infected patients with oral hairy leukoplakia are highly contagious and possible to progress acquired immunodeficiency syndrome. Therefore, the early diagnosis of oral hairy leukoplakia is very important. Taking a thorough history and human immunodeficiency virus screening test is highly recommended in case oral hairy leukoplakia is detected. In this case, a 29-year-old man presented with whitish lesion on lateral border of tongue is diagnosed as oral hairy leukoplakia and human immunodeficiency virus infection.

The value of the exfoliative cytology to the diagnosis of oral hairy leukoplakia - Case report

The value of the exfoliative cytology to the diagnosis of oral hairy leukoplakia - Case report

Oral hairy leukoplakia diagnosis by Epstein–Barr virus in situ hybridization in liquid‐based cytology

To establish a definitive diagnosis of oral hairy leukoplakia (OHL) by in situ hybridization for Epstein-Barr virus (EBV) detection with liquid-based cytology (LBC), using the ThinPrep® Pap Test, and to compare its efficacy with the traditional method of performing biopsy. Thirty-three individuals divided into three groups were included in this study. Group 1 consisted of 15 human immunodeficiency virus (HIV)-positive patients with a clinical and histopathological diagnosis of OHL on the lateral border of the tongue. Group 2 consisted of 10 HIV-positive individuals with neither OHL nor other oral lesions. Group 3 consisted of 10 immunocompetent HIV-negative individuals with neither OHL nor other oral lesions. For each patient from the three groups, exfoliative LBC was performed on the lateral border of the tongue using ThinPrep. For the patients from group 1, a 6-mm-diameter punch biopsy was obtained from the same anatomic site as the brush collection to confirm the diagnosis of OHL by histopathology with in situ hybridization. Slides were prepared for morphological cellular analysis using Papanicolaou (Pap) staining, and for EBV detection using in situ hybridization. Thirteen of the 15 patients from group 1 were confirmed on punch biopsy as OHL, providing the gold standard for the study. The sensitivity of LBC followed by a Pap-stained smear was 62% and the specificity was 90%. The sensitivity of LBC followed by in situ hybridization was 100% and the specificity was 100%. Exfoliative LBC associated with EBV in situ hybridization is a simple, effective and non-invasive diagnostic tool for OHL.

Oral Hairy Leukoplakia Which Occurred as a Presenting Sign of Acute Myeloid Leukemia in a Child

Oral hairy leukoplakia (OHL) is caused by the reactivation of a previous Epstein-Barr virus (EBV) infection in the epithelium of the tongue. Most lesions are characterized by corrugated whitish patches on the lateral border of the tongue. It is frequently associated with AIDS, but cases in patients with other immunosuppressed states have also been reported. In leukemia patients, OHL is rarely encountered, and appears only after chemotherapy. We report a case of OHL which occurred as a presenting sign of acute myeloid leukemia (AML) in a previously healthy 15-year-old child. A 15-year-old boy presented with a whitish patch on the left lateral border of the tongue. The biopsy specimen revealed papillomatosis, hyperkeratosis, acanthosis and ballooning degeneration in the stratum spinosum. The patient was EBV seropositive, and PCR analysis of EBV DNA in the lesional tissue was positive. After the diagnosis of OHL in dermatologic department, the patient was referred to pediatrics due to the abnormal peripheral blood smear, and was diagnosed with AML.

Prevalence of oral hairy leukoplakia and epithelial infection by Epstein-Barr virus in pregnant women and diabetes mellitus patients: cytopathologic and molecular study

Oral hairy leukoplakia (OHL) is generally reported in patients with severe immunosuppression, except for a few cases in individuals with moderate degree of immunodeficiency. It is a white lesion that appears mainly in the lateral border of the tongue, caused by Epstein-Barr virus (EBV). The nuclear changes caused by EBV (Cowdry A inclusion, ground glass and nuclear beading), observed in cytopathology, are specific and enough for the definitive diagnosis of OHL, independent of the identification of the virus. Here we investigated the prevalence of OHL and the presence of EBV-DNA in the lateral borders of the tongue from 90 pregnant women, 90 diabetes mellitus (DM) patients, 30 healthy individuals (negative group) and 30 HIV+ with OHL (positive group). Smears were analyzed by cytopathology and polymerase chain reaction (PCR). A case of subclinical OHL and candidiasis was identificated in a DM patient by cytopathologic analysis. PCR results demonstrated EBV-DNA in 65% of the pregnant women, in 35% of DM patients, and in 20% of the healthy individuals. We concluded that DM patients can develop OHL with a low prevalence. Furthermore, the prevalence of the EBV in lateral border of the tongue is larger in pregnant women than in healthy individuals.

Prevalence of oral hairy leukoplakia and epithelial infection by Epstein-Barr virus in pregnant women and diabetes mellitus patients: cytopathologic and molecular study

Oral hairy leukoplakia (OHL) is generally reported in patients with severe immunosuppression, except for a few cases in individuals with moderate degree of immunodeficiency. It is a white lesion that appears mainly in the lateral border of the tongue, caused by Epstein-Barr virus (EBV). The nuclear changes caused by EBV (Cowdry A inclusion, ground glass and nuclear beading), observed in cytopathology, are specific and enough for the definitive diagnosis of OHL, independent of the identification of the virus. Here we investigated the prevalence of OHL and the presence of EBV-DNA in the lateral borders of the tongue from 90 pregnant women, 90 diabetes mellitus (DM) patients, 30 healthy individuals (negative group) and 30 HIV+ with OHL (positive group). Smears were analyzed by cytopathology and polymerase chain reaction (PCR). A case of subclinical OHL and candidiasis was identificated in a DM patient by cytopathologic analysis. PCR results demonstrated EBV-DNA in 65% of the pregnant women, in 35% of DM patients, and in 20% of the healthy individuals. We concluded that DM patients can develop OHL with a low prevalence. Furthermore, the prevalence of the EBV in lateral border of the tongue is larger in pregnant women than in healthy individuals.

Risk factors for oral hairy leukoplakia in HIV‐infected adults of Brazil

Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL.

Epstein-Barr virus in oral hairy leukoplakia scrapes: identification by PCR

Oral hairy leukoplakia (OHL) is a lesion associated with a compromised immune system, and its diagnosis is determined by the demonstration of the presence of Epstein-Barr virus (EBV) in lesional tissue. The purpose of this article was to develop a simple technique to help the diagnosis of OHL, using PCR as an alternative technique to evidence EBV in scrapings. DNA samples were obtained by scraping the lateral border of the tongue of 38 adult patients: 29 HIV-positive patients (4 with clinical evidence of OHL; 4 with history of OHL, but without lesion at the moment the samples were collected; and 21 without clinical evidence of OHL), and 9 healthy volunteers for the control group. DNA was extracted from scrapes and amplified by PCR using specific primers for EBV. Of the 29 cases of HIV-positive patients, 22 (75.86%) were positive for EBV: 2 patients with clinical evidence of OHL, 4 patients with history of OHL, but without lesion at the moment the samples were collected, and 16 patients without clinical evidence of OHL. In the control group, samples of 5 (55.56%) healthy volunteers presented amplification for EBV. We concluded that the use of PCR in oral scrapes suggests a high sensitivity but low specificity for the diagnosis of OHL.

Oral hairy leukoplakia. Histopathologic and cytopathologic features of a subclinical phase.

Accurate diagnosis of oral hairy leukoplakia (OHL) is important because it may be an early indicator of undiagnosed HIV infection; moreover, it may be a prognostic indicator. Our purpose was to investigate the histopathologic features of subclinical OHL and to evaluate and support the rationale of detecting subclinical OHL with cytopathology. The Epstein-Barr virus (EBV) was detected by immunohistochemistry and in situ hybridization in 4 cases of macroscopically normal lateral borders of tongue mucosa from 8 AIDS necropsies and in none of 8 controls. The histopathologic features were specific when based on nuclear changes: Cowdry type A inclusion, ground glass, and nuclear beading. Smears were obtained from 50 patients with AIDS, without OHL, from the scraping of lateral borders of the tongue. Numerous clusters of the cells were associated with Candida organisms (30% of cases). Nuclear changes were observed in 12 patients (24%) on both sides of the tongue. We describe the histopathologic features of subclinical OHL, and our observations suggest that cytopathology can detect OHL in the subclinical phase.

Case Report of a Novel Amino Acid Deletion in Codon 67 and T69G Substitution in the Reverse Transcriptase of HIV-1

Significant progress has been made in the management of infection with HIV-1 since highly active antiretroviral therapies (HAART) were widely implemented. Nevertheless, in a growing number of patients, the effectiveness of these treatments is challenged by the emergence of viral variants of decreased susceptibility to antiretroviral agents, which leads to treatment failure [1,2]. In these cases, HIV-1 drug resistance testing provides helpful information in guiding the choice of a new regimen for patients experiencing treatment failure [3,4]. Although a large number of mutations in protease and reverse transcriptase (RT) genes (including codon insertions) have been shown to correlate with drug resistance, additional efforts are required to find mutational patterns associated with resistance [5]. In this letter we describe a rare pattern of mutations in the HIV RT gene that includes a deletion of codon 67, which to our knowledge has only been reported once before [6]. The patient is a 40-year-old woman who has been HIV-positive for 15 years, and has a long treatment history. With a diagnosis of oral hairy leukoplakia, molluscum contagiosum and varicella zoster virus in 1995, she started therapy with zidovudine and lamivudine, and nelfinavir was added 10 months later. Nine months later, the patient suffered a rise in HIV-1 viral load and a drop in CD4 cell count, and therapy was shifted to efavirenz/nelfinavir/saquinavir (a combination now recognized as ineffective). Treatment was changed again 3 months later to didanosine/ stavudine/lamivudine/hydroxyurea, after a new relapse in viral load. By March 1999, a genotypic resistance assay was performed. Both protease and RT genes were amplified from plasma HIV-RNA by RT–PCR, and sequenced using an ABI 377 automated sequencer. The following pattern was found: in the protease gene, L10I, M36I, I54V, A71V, V82A and L90M; in the RT gene, M41L, K70R, T215F, K219E, K103N, Y181C and G190A. As a result of this, amprenavir was added to the drug regimen. One year later, after a further rise in the viral load, another genotypic resistance test was performed. The results indicated not only the apparition of three new resistance-associated mutations in the HIV protease gene (K20R, L63H and I84V) but also the absence of a previously detected mutation (M36I). Interestingly, two novel abnormalities had appeared in the RT gene: a deletion of the codon 67, concomitantly with the mutations T69G and A98G, in addition to the zidovudine resistance-associated mutations

RISK FACTORS FOR AIDS ASSOCIATED NON-HODGKIN'S LYMPHOMA: A CASE-CONTROL STUDY.

S6 Background: Although non-Hodgkin's lymphoma (NHL) occurs in more than 5% of people with AIDS, little is known of risk factors for this malignancy. The one clear risk factor is severity of immune deficiency. Our study was designed to identify other risk factors for NHL, including demographic, clinical and laboratory factors. Methods: 219 people with AIDS-NHL diagnosed in Sydney prior to 1995 were compared to 219 HIV positive controls matched for degree of immune deficiency as indicated by CD4 lymphocyte count. Data on risk factors were abstracted by medical record review. Results: AIDS and cancer register linkage confirmed that all registered cases of AIDS-NHL in the study area were included. The CD4 counts of cases and controls did not differ significantly (p = 0.66). NHL risk was associated with indices of prolonged immune deficiency including longer time since seroconversion (median of 6.5 and 5.0 years in cases and controls for whom this was known, p = 0.001), lower CD4 count one year prior to diagnosis (p trend 0.003) and a prior diagnosis of mycobacterium avium complex disease (OR 3.2, 95% CI 1.2-10). Markers of immune stimulation, including raised serum globulin (p trend 0.015), IgG (p trend 0.026), and HIV p24 antigen positivity (OR 2.0, 95% CI 1.3-3.3) were also associated with risk of NHL. Indices of lytic EBV infection, including a prior diagnosis of oral hairy leukoplakia and receipt of anti-herpesvirus therapy, were not associated with risk, although receipt of ganciclovir prior to diagnosis was non-significantly protective (OR 0.51, 95% CI 0.20-1.25). Total dose of AZT received was not related to risk of NHL, and the highest dose level of ddC was associated with a decreased risk of NHL (OR 0.38, 95% CI 0.17-0.82). Conclusion: These data indicate that prolonged immune deficiency and immune stimulation are risk factors for NHL in people with HIV. This study does not support a role of anti-EBV therapy in NHL prophylaxis. Our results suggest that effective anti-HIV therapy may decrease the risk of NHL by decreasing immune stimulation.

Oral hairy leukoplakia in 71 HIV-seropositive patients: Clinical symptoms, relation to immunologic status, and prognostic significance

Background: Oral hairy leukoplakia (OHL) is a benign hyperplasia of the oral mucosa that is induced by Epstein-Barr virus. It occurs nearly exclusively in men infected with HIV. OHL is a marker of moderate to advanced immunodeficiency and disease progression in patients with HIV infection. Objective: We attempted to determine the clinical characteristics of OHL in a large group of patients infected with HIV and to analyze its relation to immune status and prognosis. Methods: A total of 456 patients with HIV-associated skin disorders were evaluated during the years 1982 through 1992. All patients had an oral examination. CD4 + cell counts were obtained within 3 months of the examination. Results: OHL was diagnosed in 15.6% of 456 patients. The median age of the patients was 35 years. OHL was found most often on the lateral aspect of the tongue; in one patient the lesion covered the entire dorsal surface of the tongue. Significant immunosuppression was present in the majority of patients at the time of OHL diagnosis (median CD4 + T-lymphocyte count, 235/μl; median CD + CD8 + ratio, 0.3). The median survival time was 20 months in patients with OHL. In patients with a higher CD4 cell count (CD4 + T lymphocyte count, ≥300/μl) the diagnosis of OHL was associated with shorter survival times (median survival time, 25 months) compared with other patients with HIV (median survival time, 52 months). Conclusion: OHL is a frequent finding in patients with HIV and indicates advanced immunosuppression. Even in patients with more than 300/μl CD4 + T lymphocytes, OHL is associated with a poor prognosis.

A rapid microwave‐in situ hybridization method for the definitive diagnosis of oral hairy leukoplakia: comparison with immunohistochemistry

As a diagnostic technique, in situ hybridization requires a long processing time, a degree of expertise and may be difficult to handle routinely in some laboratories. To simplify the in situ hybridization method, we have modified a microwave in situ hybridization technique and applied it to oral hairy leukoplakia (OHL) biopsies obtained from 10 HIV-seropositive patients (definitively diagnosed by a conventional in situ hybridization technique) with appropriate controls. It was necessary to design a novel chamber to avoid drying of sections during the hybridization step. This modified microwave in situ hybridization technique was equispecific and equisensitive to the conventional technique and it shortens the hybridization time from overnight incubation to 14 minutes. To determine the sensitivity of our microwave in situ hybridization method we applied it to previously documented tongue tissue obtained from an AIDS autopsy without clinical evidence of OHL, but found to contain Epstein-Barr virus (EBV) by conventional in situ hybridization. This tissue specimen acted as a low EBV copy number, positive control. The sensitivity of immunohistochemistry using three different commercial detection kits was compared to that of in situ hybridization on the same tissues, following optimisation steps. This included the use of 2 cycles of primary and biotinylated secondary antibodies (antibody double cycling). Clearly positive signals for EBV were detected in all OHL biopsies with the Vectastain Elite ABC and the Histostain-SP kits. The sensitivity of the three commercial detection kits was evaluated at immunohistochemistry level by their application to the low-EBV copy number positive control specimen. Signals for EBV antigen in the low copy number positive control specimen were obtained only with the Vectastain Elite ABC kit. This indicates that, in this application, use of the Vectastain Elite ABC kit gives comparable sensitivity for immunohistochemistry to that found by in situ hybridiation.