Human Herpesvirus 8 DNA Sequences Research Articles

Primary Classic Kaposi's Sarcoma Confined to the Vulva in an HIV-Negative Patient.

Dear Editor: Kaposi's sarcoma (KS) is a vascular neoplasm associated with human herpesvirus-8 (HHV-8) infection that is primarily categorized into 4 different types: endemic (African), iatrogenic (associated with immuno-suppressive therapy), AIDS-associated (rapidly progressive form in HIV-infected patients), and classic. The classic type is frequently observed in elderly male patients of Mediterranean origin and Ashkenazi Jews, presenting as an indolent disease with bluish-red (hematoma-like) cutaneous macules that tend to progress only slowly both horizontally and vertically and develop into firm angiomatous plaques and nodules. The most frequently affected sites are the lower limbs and feet; extracutaneous involvement is uncommon1. The lesions of KS are rarely localized exclusively in unusual mucocutaneous areas, thus leading to frequent diagnostic errors2. To our knowledge, there are no reports of KS confined to female external genitalia not associated with HIV infection. Here, we report the first case of classic KS restricted to the vulva in an HIV-negative patient. An 85-year-old Caucasian woman presented to our clinic for evaluation of asymptomatic vulvar lesions that appeared over the last year and progressed. Physical examination showed several brownish-violaceous angiomatous nodules and slightly raised plaques on both labia majora and minora (Fig. 1). No other significant mucocutaneous lesions were observed, and there was no evidence of inguinal lymphadenopathy. Furthermore, no other signs or symptoms suggestive of HIV infection or immunosuppression were present. The patient denied other health problems and drug use. Skin biopsy from a lesion on the right labia majora was performed for histological examination. The clinical diagnosis of KS was confirmed on the basis of revealing dermal proliferation of spindle cells, slit-like vascular spaces, and extravasated red blood cells (Fig. 2A). Immunohistochemical investigation also demonstrated positivity for D2-40, CD34, and CD31 (Fig. 2B). Moreover, polymerase chain reaction assay revealed HHV-8 DNA sequences in the lesional skin tissue; positive and negative controls were also tested and yielded the expected results. HHV-8 in the lesional tissue was also detected by in situ hybridization. Serological test for HIV was negative; chest x-ray as well as abdominal and pelvic computed tomography showed no visceral lesions. The patient refused all proposed treatments for the vulvar lesions, including intralesional therapy with bleomycin, cryotherapy, and laser photocoagulation. The 6-month follow-up did not show any disease progression. Fig. 1 (A) Several brownish-violaceous angiomatous nodules and slightly raised plaques on both the labia majora and minora, (B) magnified image of the lesions on the right labia majora. Fig. 2 (A) Dermal proliferation of spindle cells, slit-like vascular spaces, and extravasated red blood cells (H&E, ×200), (B) immunohistochemical positivity for vascular marker CD31 (×100). Overall, KS restricted to the external genitalia is a very rare finding that is more frequent in men, particularly on the penis; approximately 50 cases have been reported in the English-language literature3. Meanwhile, it is very uncommon in women, with only 9 reported cases, all of which involved the vulva2,4. Most cases of KS of the external genitalia are related to HIV infection. In fact, to our knowledge, only 15 well-documented cases of primary penile KS in HIV-negative patients have been reported5, while there are no instances of KS confined to female external genitalia not associated with HIV infection. All previous cases of vulvar KS were monolesional forms, clinically presenting as a non-specific mass, nodule, papilloma, or abscess; none were initially suspected to be KS2. The present case of classic KS restricted to the vulva is of particular interest because of its more typical clinical appearance than previous cases, with multiple lesions showing an angiomatous aspect as well as onset in an HIV-negative patient; the latter finding emphasizes the need to include KS in the differential diagnosis of vulvar disorders in immunocompetent women, especially elderly women.

Detection of Human Herpesvirus 8 in the Skin of Patients with Pityriasis Rosea

Pityriasis rosea is an acute self-limiting dermatosis with clinical and epidemiological features that suggest viral involvement. The aim of this study was to investigate a possible association between pityriasis rosea and human herpesvirus 8 (HHV-8). Lesional skin tissue was obtained from 34 Kaposi's sarcoma-negative, immunocompetent patients with typical acute phase pityriasis rosea. Nested polymerase chain reaction with specific primer for HHV-8 DNA sequences was performed and all positive results were confirmed by sequencing. Seven out of 34 lesional skin specimens (20.5%) were found to be positive for the HHV-8 genome. All the positive samples were confirmed by DNA sequencing. We conclude that, in some cases, HHV-8 is implicated the pathogenesis of pityriasis rosea.

Human herpesvirus 8 and angiosarcoma: analysis of 40 cases and review of the literature

To prove a possible involvement of the endotheliotropic human herpesvirus 8 (HHV-8) in the pathogenesis of angiosarcoma in samples from patients in a low HHV-8 seroprevalence area. A comprehensive series of angiosarcomas (n = 40) as well as positive and negative control tissues from patients with Kaposi's sarcoma, human immunodeficiency virus (HIV)-associated multicentric Castleman's disease or juvenile haemangioma, respectively, was analysed with two sensitive methods: immunohistochemical staining for the HHV-8 latency-associated nuclear antigen 1 (LANA-1); and polymerase chain reaction (PCR) for HHV-8 VP23 DNA sequences. None of the angiosarcoma cases and none of the negative control samples (juvenile haemangiomas) revealed positive immunohistochemical staining with the LANA-1 antibody. In contrast, HHV-8 LANA-1 was clearly detected in all analysed cases of Kaposi's sarcoma and multicentric Castleman's disease. These results were confirmed by PCR assay at the DNA level. In conclusion, the great majority of angiosarcomas investigated to date, including the series of 40 angiosarcomas analysed here, does not contain HHV-8 DNA sequences or protein. This argues against a relevant role of the endotheliotropic HHV-8 in the pathogenesis of angiosarcoma and, for vascular diseases, speaks in favour of a relatively restricted pathogenic role of HHV-8 to Kaposi's sarcoma and multicentric Castleman's disease.

Salivary Lactoferrin Is Recognized by the Human Herpesvirus-8

Human herpesvirus-8 (HHV-8) is commonly detected in all epidemiologic forms of Kaposi's sarcoma. Despite the broad cellular tropism of HHV-8, studies on mucosal shedding of HHV-8 have shown that infectious particles are restricted to saliva isolated from the oropharynx. We used biotinylated purified HHV-8 particles in a direct binding assay to whole clarified human salivary samples isolated from HHV-8-infected and uninfected individuals. We found that the major binding activity was carried out by a protein of 78-kDa size, which was further characterized as human lactoferrin (hLf) using 2-D electrophoresis and MALDI-ToF analysis. Preliminary comparison of HHV-8 binding activity of 76 salivary samples from HHV-8-infected and uninfected individuals showed that 7.8% of the uninfected population exhibited a form of Lf not recognized by HHV-8. Deglycosylation of hLf by PNGase F did not reduce HHV-8 binding activity, whereas endoproteinase cleavage of native hLf generated a non-glycosylated 8-kDa peptide recognized by HHV-8 particles and was located at the position Ala606-Tyr679 in the native hLf amino acid sequence, corresponding to the C-terminal region of the glycoprotein. This work identify the lactoferrin in saliva as a ligand for HHV-8 and suggests that this glycoprotein could be used as a carrier for the viral particles.

Kaposi's sarcoma: an update.

While there have been many important advances in the study of Kaposi's sarcoma (KS), it remains both a challenge and an enigma in many ways. Kaposi's original description of "multiple idiopathic hemorrhagic sarcoma[s]" in patients who died within 2-3 years resembles KS in AIDS more than classic KS in elderly men of Italian, Jewish, or Mediterranean lineage, in whom the disease is usually benign. KS had been evident in about one-third of those with early AIDS, often as its presenting sign, a pattern markedly reduced in recent times since the introduction of highly active anti-retroviral therapy (HAART). The most important advance has been the convincing etiologic linkage of KS with human herpesvirus 8 (HHV-8), which is necessary but not sufficient. It has a low prevalence in the general population of the USA and UK, with an intermediate rate in Italy and Greece, and a high one in Uganda. KS risk may be significantly lower in AIDS patients with a history of anti-herpes therapy. Many aspects of HHV-8, including its transmission pattern and different genospecies, are being scrutinized. The diagnosis of KS may be difficult. One should be aware of KS clinical variants, including telangiectatic, eccymotic, and keloidal KS. One must consider a number of other disorders, including bacillary angiomatosis. HHV-8 DNA sequences in dermatofibromas and other tumors should probably not be viewed as representing a marker for KS. Therapeutic options vary for KS. Intralesional and low-dose outpatient intravenous vinblastine may be valuable, as immunosuppression with KS is not a good idea if it can be avoided. Anti-herpes virus therapy may have potential for wide use, especially in preventing the development of KS in at risk populations, such as HHV-8 seropositive individuals undergoing transplantation surgery.

Human herpesvirus-8 infection in pregnancy and labor: lack of evidence of vertical transmission.

To investigate whether vertical transmission of the human herpesvirus 8 (HHV-8) may occur during pregnancy or at delivery, we enrolled 295 women recruited attending the Division of Obstetrics and Gynecology of a University Teaching of Rome Tor Vergata, S. Eugenio Hospital. The study population was divided in two groups: 245 pregnant women who underwent amniocentesis for genetic screening at 16-18 weeks gestation (group 1) and 50 women at the childbirth (group 2). Maternal blood was obtained from all women. Amniotic fluid (group 1) and cord blood (group 2) were obtained at midtrimester and at delivery, respectively. The presence of anti-HHV-8 antibodies in serum samples was investigated by an immunfluorescence assay. All amniotic fluids, maternal blood, and cord blood samples from HHV-8 seropositive women were tested for the presence of HHV-8 DNA sequences by the polymerase chain reaction. Thirty women, 27 of the group 1 and three of the group 2, were found to have anti-HHV-8 antibodies. Two neonates of the three seropositive mothers of the group 2 had anti-HHV-8 antibodies in cord blood. HHV-8 DNA sequences were detected in the blood of one woman of the group 2. None of the amniotic fluid and cord blood samples had detectable HHV-8 DNA sequences. This study suggests that vertical transmission of HHV-8 is unlikely or, at least, very rare.

Human herpesvirus-8-positive body cavity-based lymphoma involving the atria of the heart: A case report

We describe an unusual case of a body cavity-based lymphoma, otherwise termed primary effusion lymphoma (PEL), involving the atria of the heart of an HIV-seropositive patient. This is the first reported case of the involvement of the heart by this rare lymphoma. This HIV-related lymphoma represents a distinct B-cell malignancy associated with human herpesvirus-8 (HHV-8) infection. It is characterized by involvement of body cavities, with infrequent evidence of organ or bone marrow infiltration. The tumor cells are large, nucleolated with an immunoblastic or anaplastic appearance, positive for activation markers, such as CD30, and negative for B-cell and T-cell immunophenotypic markers. Integration of HHV-8 DNA sequences is considered the hallmark of PEL. The tumor demonstrates frequent association with Epstein–Barr virus (EBV) and uniform absence of c-myc oncogene rearrangement, unlike most other HIV-related lymphomas.

Primary human herpesvirus 8 infection in immunocompetent children.

Human herpesvirus 8 (HHV-8) infection causes Kaposi sarcoma and lymphoproliferative disorders in immunosuppressed adults. Its manifestations in immunocompetent hosts are unknown. To determine whether HHV-8 primary infection is symptomatic in immunocompetent children and to identify the epidemiological and virological correlates of HHV-8 infection. Prospective cohort study conducted in the pediatric emergency department of a hospital in Alexandria, Egypt, between December 1, 1999, and April 30, 2000. Eighty-six children aged 1 to 4 years who were evaluated for a febrile syndrome of undetermined origin. Serological assay and polymerase chain reaction of blood and saliva samples for HHV-8. Information on potential risk factors for HHV-8 infection was also collected. Thirty-six children (41.9%) were seropositive; HHV-8 DNA sequences were detected in 14 (38.9%) of these 36 children (detected in saliva in 11 of 14). Significant associations were found between HHV-8 infection and close contact with at least 2 other children in the community (36 of 63 vs 6 of 23 for <2 children; adjusted odds ratio [OR], 3.50; 95% confidence interval [CI], 1.11-12.22) and admission to the emergency department in December or January (28 of 47 vs 14 of 39 for February-April; adjusted OR, 3.15; 95% CI, 1.23-8.58). Six children had suspected primary HHV-8 infection; all but 1 had a febrile cutaneous craniocaudal maculopapular rash, which was more common among these children (5 of 6 vs 10 of 75; P<.001). For 3 of these 6 children, a second blood sample was obtained after the convalescence phase, and all 3 seroconverted for HHV-8. Primary infection with HHV-8 may be associated with a febrile maculopapular skin rash among immunocompetent children. The finding of HHV-8 DNA sequences in saliva supports the hypothesis that transmission through saliva is the main mode of transmission in the pediatric age group.

Human herpesvirus 8 DNA sequences are present in bone marrow from HIV-negative patients with lymphoproliferative disorders and from healthy donors.

Bone marrow (BM) from patients affected by multiple myeloma (MM), exhibiting monoclonal gammopathy of undetermined significance (MGUS) or with non-Hodgkin lymphoma (NHL) as well as from healthy donors were investigated for the presence of human herpesvirus-8 (HHV-8) DNA sequences. ORF 26 sequences were detected in 36--56% of the patients and in 29% of the controls. In a few cases, two other HHV-8 DNA sequences were also detected. These observations indicate that the presence of the HHV-8 genome in BM is relatively common in different groups of patients as well as in healthy individuals and do not support an alleged role for HHV-8 in MM.

Retiform hemangioendothelioma: Another tumor associated with human herpesvirus type 8?

Retiform hemangioendothelioma is a rare low-grade angiosarcoma of the skin. It shares some clinical characteristics with Kaposi’s sarcoma, a tumor with known human herpesvirus 8 (HHV-8) association. We report a case of retiform hemangioendothelioma in which we detected HHV-8 DNA sequences. (J Am Acad Dermatol 2000;42:290-2.)

A search for human herpesvirus 8(HHV-8) in HIV-1 infected mothers and their infants does not suggest vertical transmission of HHV-8

A search for human herpesvirus 8(HHV-8) in HIV-1 infected mothers and their infants does not suggest vertical transmission of HHV-8

Detection of human herpesvirus 8 in Korean Kaposi's sarcoma cases by polymerase chain reaction and in situ polymerase chain reaction.

Several infectious agents, including herpesvirus-like particles, had been suggested as possible candidates for the development of Kaposi's sarcoma (KS), and a new herpesvirus, human herpesvirus 8 (HHV-8), was recently identified in the vast majority of KS lesions, irrespective of their association with human immunodeficiency virus (HIV) infection. However, the etiologic role of HHV-8 in KS remains controversial. We undertook this study to screen for and localize the presence of HHV-8 in KS in Korea. A total of 46 paraffin-embedded specimens were studied, including KS, hemangioproliferative disorders, and 10 non-KS lesions from HIV-positive patients. We performed nested polymerase chain reaction (PCR) and in situ PCR with HHV-8 specific primers. HHV-8 DNA sequences were detected in 8 of 11 KS specimens. All specimens of hemangioproliferative disorders, non-KS lesions from HIV-positive patients, and other skin samples were negative for HHV-8. When sequencing PCR products, the sequences were almost identical with the prototypic sequence for HHV-8. In PCR-positive tissues, in situ PCR staining of HHV-8 localized to nuclei of endothelial cells and perivascular spindle-shaped tumor cells. The results of this study suggest that HHV-8 is not widespread and has a certain causative role in the development of KS. Further studies, including serological and animal studies, will be helpful to appreciate an epidermiological link and pathogenetic mechanism between HHV-8 and KS.

HHV-8 in Renal Transplant

A rare but serious complication of solid organ transplantation is Kaposi's sarcoma (KS). Human herpesvirus 8 (HHV-8) has recently been linked to the development of KS; HHV-8 DNA sequences have been identified in KS lesions, and HHV-8 infection is associated with KS in …

Usefulness of molecular detection of human herpesvirus-8 in the diagnosis of Kaposi sarcoma by fine-needle aspiration.

Kaposi sarcoma (KS), a multifocal angioproliferative disorder, occurs most commonly in patients with AIDS, in whom it remains an important cause of morbidity and mortality. KS is often in the differential diagnosis in HIV-infected patients undergoing fine-needle aspiration (FNA). FNA diagnosis of KS is usually made by morphologic observation of scant tissue fragments composed of bland spindle cells and crush artifact. Human herpesvirus-8 (HHV-8) has been identified by polymerase chain reaction (PCR) amplification of DNA samples isolated from various epidemiologic forms of KS. In an attempt to improve the accuracy of KS diagnosis by FNA, we analyzed for the presence of HHV-8 DNA in 13 spindle-cell lesions evaluated by FNA: KS, 8 cases; granulomatous inflammation due to Mycobacterium avium-intracellulare, 1; nodular fasciitis, 1; dermatofibrosarcoma protuberans, 1; dermatofibroma, 1; benign spindle-cell lesion of nerve sheath origin, 1; and 2 lesions with lymphoid hyperplasia. DNA isolated from archival Wright-Giemsa-stained glass slides was used for the PCR amplification of the HHV-8 DNA sequences. All of the cases diagnosed as KS and 1 of the lymphoid hyperplasia cases were PCR-positive for HHV-8 DNA, while all other cases of spindle-cell lesions were negative. The molecular demonstration of HHV-8 DNA may be a useful adjunct in the diagnosis of KS by FNA.

High prevalence in Central Africa of blood donors who are potentially infectious for human herpesvirus 8.

In western countries, the transmission of human herpesvirus 8 (HHV-8) via blood transfusion has been recently postulated. In sub-Saharan African, the incidence of HHV-8-associated Kaposi's sarcoma and the seroprevalence for HHV-8 in autochthonous populations are high. The aim of this study was to estimate the prevalence of blood donations potentially infectious for HHV-8 in the general adult population of Central Africa. Forty-nine blood donors at the Centre de Transfusion Sanguine in Bangui, the capital of the Central African Republic, were selected. Forty-five inpatients of Broussais Hospital, Paris, France, who were known to be seronegative for HIV and hepatitis B and C viruses and who had not received heart or kidney transplants, were chosen as a European "control" group for comparison. HHV-8 DNA sequences were detected in peripheral blood mononuclear cells by nested polymerase chain reaction using primer sets located in the HHV-8 open reading frame 26. Eleven (22.5%; 95% CI: 12%-37%) of 49 blood donors were positive for HHV-8. Three (6%) were HIV-1 seropositive. Two (67%) of the 3 HIV-infected blood donors were also positive for HHV-8. All blood donors were apparently healthy; none was known to suffer from Kaposi's sarcoma. Only one (2.2%) control was carrying HHV-8 DNA on the peripheral blood mononuclear cells. The prevalence of HHV-8 was higher in blood donors from Bangui than in patients from Broussais Hospital. HHV-8 infection is highly prevalent in an apparently healthy adult population from Central Africa, which raises concerns about HHV-8 transmission through transfusion in this setting.

PCR assay fails to detect molluscum contagiosum virus-related sequences in AIDS-related Kaposi's sarcoma

Previous PCR-based studies have demonstrated the presence of various viral DNA or RNA sequences in Kaposi's sarcoma (KS) tissues. To date, only human herpesvirus 8 (HHV-8) DNA sequences are found consistently in KS. The putative role of this agent in KS pathogenesis remains, however, to be determined; HHV-8 could infect populations endemically and could be reactivated in patients with KS. A close association between AIDS-related KS and molluscum contagiosum occurrence was found and this study was conducted primarily to search for the presence of molluscum contagiosum virus DNA sequences in KS. Frozen KS samples were examined for the presence of both HHV-8 and molluscum contagiosum virus DNA sequences by PCR. Despite a high rate of co-infection, no molluscum contagiosum virus (MCV) DNA sequence could be found in the KS samples whereas HHV-8 was uniformly detected. These results suggest that the high prevalence of MCV in AIDS patients with KS relies on a mode of transmission common for HHV-8 and molluscum contagiosum virus rather than on a multiviral etiology of KS. They may also indicate a particular susceptibility of the host to viral reactivation. If this is so, the failure to detect MCV DNA sequences in KS tissues by PCR indicates that locally produced or released cyotokines are not involved in the latter process.

Absence of HHV-8 DNA sequences in malignant mesothelioma.

Human herpesvirus 8 (HHV-8) associated primary effusion lymphomas arise and grow in the body cavities as effusions, but it is not known whether the lining of body cavities and mesothelium...

Human herpesvirus 8 variants in sarcoid tissues

The cause of sarcoidosis is unknown, although mycobacteria have been implicated. We examined sarcoid tissues for human herpesvirus 8 (HHV-8) in addition to mycobacterial genomic sequences. Biopsy samples from 17 patients with sarcoidosis were studied (eight transbronchial, 27 lymph node, two skin, and two oral mucosa). We used tissues (n = 137) from 96 patients without sarcoidosis as negative controls. A nested PCR was applied to amplify a segment of open reading frame (ORF) 26 of the HHV-8 genome, and a heminested PCR was to amplify a segment of ORF 25 of HHV-8 and of the 16 S rRNA gene of mycobacteria. Differences in base sequences of the amplified fragments were resolved with single-strand conformation polymorphism and dideoxy sequencing. HHV-8 ORF 26 DNA was detected in significantly higher proportions of sarcoid than of non-sarcoid tissue samples from lung (8/8 vs 0/54; p < 0.0001), lymph nodes (26/27 vs 6/29; p < 0.0001), skin (2/2 vs 0/17; p = 0.006), and oral tissues (2/2 vs 1/13; p = 0.029). 31 (82%) of the 38 ORF 26 DNA-positive sarcoid specimens were also positive for ORF 25 DNA. For mycobacteria-like 16 S rRNA DNA, the proportion positive was significantly higher in sarcoid than non-sarcoid tissues for lymph node samples (11/27 vs 2/29; p = 0.003) but not for other tissues (lung 3/8 vs 22/54; skin 2/2 vs 15/17; and oral tissues 1/2 vs 0/13). Overall, the prevalence of HHV-8 ORF 26 sequences was higher in sarcoid tissues than in non-sarcoid tissues (p < 0.0001). When patients whose tissues were included in a masked phase of the study were treated as units of analysis, eight of eight sarcoidosis patients were positive for HHV-8 ORF 26 DNA, compared with three of 56 control patients (p < 0.0001); for mycobacteria-like sequences, three of eight sarcoidosis patients were positive, compared with four of 56 controls (p = 0.0464). The HHV-8 ORF 26 sequences, ten of which were unique, could be segregated into four groups according to peptide motifs. In seven of nine patients from whom biopsy samples were taken from various sites, different sequences were recovered. The mycobacterial sequences amplified from sarcoid tissues were also varied, but none was homologous to those of known species. Variant HHV-8 DNA sequences are found in a wide range of sarcoid but not non-sarcoid tissues. Mycobacteria-like 16 S rRNA sequences are more frequently present in sarcoid lymph nodes and not in other tissue types, but do not indicate infection by a particular mycobacterial species.

Human Herpesvirus 8 DNA Sequences in Blistering Skin From Patients With Pemphigus

Human herpesvirus 8 (HHV-8) has been detected in Kaposi sarcoma (KS) and other lesions in patients both seropositive and seronegative for the human immunodeficiency virus (HIV). Kaposi sarcoma has been reported to develop in a disproportionate number of patients with pemphigus. Since HHV-8 is so strongly associated with KS, we wondered whether HHV-8 is present in pemphigus lesions from patients without KS or HIV infection. Pemphigus lesions and skin from healthy individuals were coded in a blinded fashion. Tissue-extracted DNA was tested using polymerase chain reaction, Southern blot hybridization, and automated sequencing of the polymerase chain reaction products for the presence of HHV-8 DNA. Six patients had pemphigus foliaceus, 6 had pemphigus vulgaris, and 2 had KS; 10 healthy individuals were used as controls. All 24 patients were HIV seronegative. Lesional skin from 4 of the 6 patients with pemphigus vulgaris, all 6 of the patients with pemphigus foliaceus, and both positive controls (KS) tested positive for HHV-8 DNA. Furthermore, the HHV-8 DNA sequences for KS330(233) differed between all 6 DNA specimens from pemphigus foliaceus, while 3 of the 4 DNA specimens from pemphigus vulgaris were identical. However, HHV-8 DNA was absent in all normal human skin analyzed. This report expands the spectrum of lesions found to contain HHV-8 DNA sequences and suggests that HHV-8 might have trophism for pemphigus lesions.

Detection of human herpesvirus 8 DNA sequences in peripheral blood mononuclear cells of children

Human herpesvirus 8 (HHV-8) DNA sequences were examined in peripheral blood mononuclear cell (PBMC) DNA samples of 56 children, 15 healthy adults, and 10 renal transplant patients by the polymerase chain reaction (PCR). The PCR amplification was carried out using the published KS330(233) primer pairs to amplify HHV-8 DNA sequences. The PCR-amplified products were confirmed by Southern blot hybridization with radiolabeled 233 bp HHV-8 DNA fragment, which was cloned and sequenced from the PCR-amplified product of Kaposi's sarcoma tissue. Six PCR-amplified product of four children and two renal transplant patients were cloned and sequenced. HHV-8 DNA sequences were detected in 36 of 56 (64%) normal children, in 12 of 15 (80%) healthy adults, and in all 10 renal transplant patients by Southern blot hybridization of PCR-amplified products. Six PCR-amplified products were confirmed by sequencing. These results suggest that HHV-8 infection is prevalent in the Japanese population with infection occurring in early childhood.