Thirty biopsies of oral mucosal lesions and normal oral mucosa were obtained from 26 HIV-seropositive individuals and studied for virus infections with Epstein-Barr virus-specific DNA probes (EBV). In situ DNA hybridization was carried out on frozen and formalin-fixed, paraffin-embedded tissues. Specifically bound biotinylated virus probes were detected with the streptavidin-gold-silver technique and visualized by standard and interference reflection microscopy. In 9/30 biopsies, EBV DNA was clearly demonstrated in the upper two thirds of oral epithelia. This finding corresponded to peculiar cytopathic effects including ground glass nuclei, basophilic nuclear inclusions, and ballooning of the cytoplasm, which were concentrated in the upper two or three layers of the stratum spinosum. Cytopathic effects together with the demonstration of EBV DNA were demonstrated in seven cases of tongue mucosa, and two cases derived from the gingiva. When comparing clinical and pathological findings with DNA detection rates, we saw 5/9 hairy leukoplakias associated with EBV infections. Four positive cases (two samples from the tongue, two gingival specimens) had not been regarded as hairy leukoplakia clinically. EBV infection of the oral epithelium occurred in male homosexuals (7 cases) and in male/female intravenous drug abusers (2 cases). Among the nine EBV-positive cases, 2 patients were asymptomatic, 4 patients were grouped into the ARC-, and 3 individuals into the AIDS-category. We conclude that HIV-seropositive patients are particularly prone to develop productive EBV infections in oral epithelia. This infection most frequently appears at the lateral border of the tongue, but may also occur at other sites of the oral cavity, and may already exist in a preclinical stage prior to the development of oral white lesions (hairy leukoplakia).
