Molecular characterization of Kaposi's sarcoma associated herpesvirus (KSHV) from patients with AIDS-associated Kaposi's sarcoma in Sao Paulo, Brazil

BACKGROUND

Kaposi's sarcoma (KS) is caused by Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8), the eighth Herpesvirus found to infect humans. The molecular epidemiology of KSHV is related closely to ethnicity and geographical location of studied populations. There is little epidemiological and molecular information about KSHV strains circulating in Brazil.

OBJECTIVES

To characterize KSHV strains isolated from AIDS patients with Kaposi's sarcoma (AIDS-KS) in Sao Paulo, Brazil, and to examine associations between KSHV subtypes, ethnicity and HIV risk categories.

METHODS

AIDS-KS patients were recruited consecutively at the largest AIDS reference hospital in Sao Paulo. Fragments (420 bp) of the VR1 and VR2 regions of KSHV open reading frame (ORF) K1 were amplified by nested PCR and sequenced directly.

RESULTS

We analysed 37 samples from 33 patients, and found subtypes A-C in 48%, 21% and 30% of patients respectively, including two patients infected with subtype A5, a first report from Brazil. Sexual orientation was associated with subtype: 12/14 (86%) patients with subtype A were male homo/bisexual, compared with 3/8 (38%) among patients infected with subtype C (P = 0.05). A higher proportion of male patients with subtype C were of Caucasian origin (7/8 (87%)), compared with 7/16 (44%) among male patients with subtype A (P = 0.08).

CONCLUSIONS

This first detailed report of KSHV subtypes among AIDS-KS patients in Brazil reports the first isolation of KSHV subtype A5 in this country, and suggests KSHV strain transmission between different ethnic groups, and association of specific strains with sexual orientation.

Molecular epidemiology of Kaposi's sarcoma herpesvirus (KSHV) in Cuban and German patients with Kaposi's sarcoma (KS) and asymptomatic sexual contacts

Kaposi's sarcoma (KS) shows a distinct geographical and ethnic distribution. The variable K1 gene serves to differentiate the KSHV subtypes A-E, M, N, and Q. Phylogenetic characterization of 19 classical and epidemic German KS specimens revealed the Eurasian KSHV subtypes C (n = 13, including 6 classical KS) and A (n = 6), while 27 Cuban specimens showed a variety of different subtypes (A: n = 16, 4 being A5; C: n = 8; B: n = 2; and the new subtype E: n = 1). Three pairs of isolates from KS patients and peripheral blood mononuclear cells (PBMC) of their sexual partners without KS were studied for the first time and found identical, strongly arguing for sexual transmission of KSHV in this unique cohort. The unique ethnic background of the Cuban population may explain the variety of different KSHV strains.

Molecular epidemiology and KSHV K1 subtypes in a Cuban AIDS-Kaposi's sarcoma population

Kaposi's sarcoma-associated herpesvirus (KSHV) is detected consistently in Kaposi's sarcoma (KS). Because of its dramatic sequence variation, the K1 gene has been used to classify KSHV. We found a diverse array of KSHV subtypes A1, A2, A3, A5, B1, B2, and C3 in 23 Cuban KS samples containing several novel sporadic insertions/deletions in subtypes A and C. The molecular epidemiology of the KSHV subtypes seems to reflect the unique mixed ethnic background of the Cuban population.

Genotypic distribution of human herpesvirus-8 strains circulating in HIV-positive patients with and without Kaposi’s sarcoma in Hungary

Open reading frame (ORF) 26 of human herpesvirus-8 (HHV-8) from peripheral blood samples of 15 Hungarian HIV-positive patients with or without Kaposi's sarcoma (KS) were amplified and sequenced. Four variants of HHV-8 were identified according to ORF 26 genotyping. Most of the samples were shown to be subtype A3, however, subtypes A, B3/C2/C2', and C3 (ORF 26 region) were also identified. The ORF 26 subtypes A and C3 of HHV-8 were only recovered from patients with KS while A3 was dominant in KS negative cases. The amplification of the hypervariable ORF K1 gene was successful only from 2 of the same 15 patients. Sequence analysis of the amplified ORF K1/VR1 regions identified subtype A3 from 2 patients with AIDS-associated KS. A novel ORF K1/VR1 variant belonging to subgroup A' was detected in a different sample in one of them. Amplification of the ORF K15, another representative locus for HHV-8 genotyping, was not successful from any of the peripheral blood samples. Unsuccessful amplification of the terminal K1 and K15 ORFs from peripheral blood samples suggests that KS biopsy specimens are needed for complete genotyping of HHV-8 strains from Hungary.

Genotypic profile of human herpesvirus 8 (Kaposi's sarcoma-associated herpesvirus) in urine

Human herpesvirus 8 (HHV-8) open reading frame K1 sequences amplified from the urine of 5 of 78 (6.4%) infected people in Malawi were monotypic. In two people, urinary and oral sequences were genotypically different. Comprehensive evaluation of HHV-8 transmission may require characterization of HHV-8 shed both in urine and orally.

Human herpesvirus 8 (HHV8) sequence variations in HHV8 related tumours in Okinawa, a subtropical island in southern Japan

BACKGROUND

Although rare in mainland Japan, classic Kaposi's sarcoma (KS) is frequently reported in Okinawa, a subtropical island in southern Japan. Human herpesvirus 8 (HHV8) has been identified in the tumours and geographical differences occur.

AIM

To sequence HHV8 in classic and AIDS associated KS in Okinawa.

MATERIALS/METHODS

Eight classic KS cases, one AIDS associated KS, five granuloma pyogenicum cases, two inflammatory pseudotumours, two Castleman's disease cases, one angiosarcoma, and one primary effusion lymphoma (PEL) were studied. As a control, HHV8 positive cultured PEL cells (TY-1) were used. The presence of HHV8 sequences was evaluated by PCR and in situ hybridisation. PCR products were sequenced.

RESULTS

There were no histological differences among KS resulting from the different virus genotypes. HHV8 was detected in all cases of KS, in one PEL, and one granuloma pyogenicum. Eight classic KS cases and one granuloma pyogenicum were infected with HHV8 genotype II/C (K1 region) or subtype C (ORF26 region), which had a five amino acid deletion at K1 VR2 region. An AIDS associated KS and a PEL were infected with type I/A virus.

CONCLUSION

In Okinawa, classic KS cases and one granuloma pyogenicum case were infected with HHV8 genotype II/C, also classified as subtype C. AIDS associated KS and PEL were infected with a different HHV8 (genotype I/A), similar to that found in the USA. In Okinawa, HHV8 infection is more than four times higher than in mainland Japan, resulting in many cases of KS because of HHV8 genotype II/C infection.

Seroprevalence of antibodies against human herpesvirus 8 in a population of renal transplant recipients at Hôtel-Dieu de Québec Hospital

We conducted a seroepidemiologic study to determine the prevalence of anti-human herpesvirus 8 antibodies in a renal transplant population at Hôtel-Dieu de Québec Hospital. Testing for immunoglobulin G antibodies against lytic and latent antigens was performed on serum samples from 150 renal transplant patients. Human immunodeficiency virus-positive patients with confirmed Kaposi's sarcoma were used as positive controls. None of the renal transplant patients tested positive.

Molecular epidemiology of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 strains from Russian patients with classic, posttransplant, and AIDS-associated Kaposi's sarcoma

We report the molecular characterization of 38 new Kaposi's sarcoma-associated herpesvirus (KSHV) strains from Russian patients with either classic (25 cases), epidemic/AIDS-associated (7 cases), or posttransplant/immunosuppressed patients (6 cases), or Kaposi's sarcoma (KS). While a complete sequence of the K1 gene (870 bp) was obtained from 30 strains, only partial sequences of the hypervariable regions VR1 (372 bp) and/or VR2 (381 bp) of the K1 gene were obtained from eight strains of KS paraffin blocks. Sequence comparison and phylogenetic studies indicate that the novel KSHV strains belong to either the A subtype (28 cases) or the C subtype (10 cases). Within the 28 strains of A subtype, 24 (86%) belong to the large A' subgroup, mostly A1 and A1' clades, and 4 belong to the A" subgroup, mostly A3 clade. Within the 10 strains of subtype C, 4 were of C' subgroup, and 6 of the C". Some molecular variants of subtype A' were observed, with 3 strains exhibiting an insertion of a single amino acid at the position 65 and 2 strains (both from AIDS-KS) with an unique deletion of 17 amino acids in the VR2 region. Polymerase chain reaction-based subtyping of the K14.1 genomic region indicated that most (23/32) of the novel strains belonged to the P subtype. The results indicate that despite a wide genetic diversity of A and C K1 subtypes of KSHV strains present in Russia, most are closely related and belong to the A1 or A1' molecular clades suggesting a common origin. This study also expands the data regarding the absence of any correlation between a K1 molecular subtype and a specific KS type (classic, epidemic, or posttransplant), as well as between the K1 and K14.1 molecular subtypes.

Genotypic characterization of Kaposi's sarcoma-associated herpesvirus in asymptomatic infected subjects from isolated populations

Molecular epidemiological studies of Kaposi's sarcoma-associated herpesvirus (KSHV) have concentrated on characterization of viral strains in tumour biopsy samples from Kaposi's sarcoma (KS) patients, mostly obtained in the United States and Europe. Tumour biopsies are a convenient source of viral DNA, as they have a high viral load compared to peripheral blood. However, sequences obtained from biopsies may not be representative of viral strains in asymptomatic subjects and information on ethnicity is often not available. Here, a population-based approach has been used to study the molecular and seroepidemiology of KSHV in isolated populations in Ecuador and Botswana. Amerindians in Ecuador had a variable prevalence of KSHV and all strains characterized were of subtype E, based on K1 sequencing. All Amerindian strains had predominant (P)-type K15 alleles and had sequences in both T0.7 and ORF 75 that appeared to be characteristic of these strains. The prevalence of KSHV in two ethnic groups in Botswana was extremely high. K1 sequences from both Bantu and San subjects were mostly of subtypes B and A5, which are typical of African KSHV strains, but the sequence from one San subject did not cluster with any known subtype. Considerable heterogeneity was seen in the T0.7 and ORF 75 genes in the San subjects and one had a minor (M)-type K15 allele. The heterogeneity of the KSHV strains found in these subjects from Botswana contrasts with the homogeneity of KSHV strains in Amerindians, reflecting differences in the evolutionary history of these populations.

Multiple human herpesvirus-8 infection

In Malawian patients with Kaposi sarcoma (KS) and their relatives, we investigated nucleotide-sequence variation in human herpesvirus-8 (HHV-8) subgenomic DNA, amplified from oral and blood samples by use of polymerase chain reaction. Twenty-four people had amplifiable HHV-8 DNA in >1 sample; 9 (38%) were seropositive for human immunodeficiency virus type 1, 21 (88%) were anti-HHV-8-seropositive, and 7 (29%) had KS. Sequence variation was sought in 3 loci of the HHV-8 genome: the internal repeat domain of open-reading frame (ORF) 73, the KS330 segment of ORF 26, and variable region 1 of ORF K1. Significant intraperson/intersample and intrasample sequence polymorphisms were observed in 14 people (60%). For 3 patients with KS, intraperson genotypic differences, arising from nucleotide sequence variations in ORFs 26 and K1, were found in blood and oral samples. For 2 other patients with KS and for 9 people without KS, intraperson genotypic and subgenotypic differences, originating predominantly from ORF K1, were found in oral samples; for the 2 patients with KS and for 4 individuals without KS, intrasample carriage of distinct ORF K1 sequences also were discernible. Our findings imply HHV-8 superinfection.

Molecular analysis of human herpesvirus 8 by using single nucleotide polymorphisms in open reading frame 26

Human herpesvirus 8 (HHV-8) can be classified into distinct subtypes on the basis of sequence polymorphisms in several open reading frames (ORFs). We analyzed the subtypes of HHV-8 in 59 human immunodeficiency virus-infected Japanese patients by using polymorphisms in ORF26 and found that over two-thirds of the HHV-8 isolates fell into major subtype A. We also found that single nucleotide polymorphisms (SNPs) at nucleotide positions 1032 (C-to-A substitution) and 1055 (G-to-T substitution) in HHV-8 ORF26 were correlated with increased susceptibility to Kaposi's sarcoma, compared to the results obtained with HHV-8 with wild-type nucleotides at these positions (P = 0.0106). This observation suggests that molecular heterogeneity of the HHV-8 genome affects the biological properties of HHV-8, resulting in different clinical phenotypes of HHV-8 infection. Since sensitive PCR of ORF26 allowed us to analyze the SNPs by using peripheral blood from HHV-8-infected patients, the ORF26 SNPs will be a potent tool for investigating the pathogenesis of HHV-8 infection.

Analysis of 4.3 kilobases of divergent locus B of macaque retroperitoneal fibromatosis-associated herpesvirus reveals a close similarity in gene sequence and genome organization to Kaposi's sarcoma-associated herpesvirus

We previously identified retroperitoneal fibromatosis-associated herpesvirus (RFHV) as a simian homolog of Kaposi's sarcoma-associated herpesvirus (KSHV) in a fibroproliferative malignancy of macaques that has similarities to Kaposi's sarcoma. In this report, we cloned 4.3 kb of divergent locus B (DL-B) flanking the DNA polymerase gene from two variants of RFHV from different species of macaque with a consensus degenerate hybrid oligonucleotide primer approach. Within the DL-B region of RFHV, viral homologs of the cellular interleukin-6, dihydrofolate reductase, and thymidylate synthase genes were identified, along with a homolog of the gammaherpesvirus open reading frame (ORF) 10. In addition, a homolog of the KSHV ORF K3, the modulator of immune recognition-1, was identified. Our data show a close similarity in sequence conservation, gene content, and genomic structure between RFHV and KSHV which strongly supports the grouping of these viral species within the same RV-1 rhadinovirus lineage and the hypothesis that RFHV is the macaque homolog of KSHV.

HHV-8 subtypes in South Africa: identification of a case suggesting a novel B variant

Human herpesvirus 8 (HHV-8) has been identified as the causative agent for all forms of Kaposi's sarcoma and is also associated with the development of body cavity-based B-cell lymphomas and multicentric Castleman's disease. HHV-8 genomes are now classified into five major subtypes (A-E) that reflect sequence heterogeneity in the highly variable open reading frame (ORF) K1. To identify HHV-8 subtypes associated with different forms of Kaposi's sarcoma, we compared the ORF 26 and ORF-K1 gene sequences from South African patients with the prototype strains of the major subtypes, as well as published sequences from other African strains. DNA prepared from Kaposi's sarcoma biopsies and/or peripheral blood lymphocytes were available from 14 patients with postrenal transplant (iatrogenic) Kaposi's sarcoma, six patients with the African endemic form, and one patient with AIDS-related body cavity-based B-cell lymphoma. We identified a B2 subtype in six patients, four of whom also had a novel B5 type ORF 26 polymorphism. Two patients had B2 type patterns for both the ORF 26 and ORF-K1 genes. The ORF-K1 subtype A5 was identified in samples from three patients with a B3/C2 type polymorphism in the ORF 26 gene. A novel ORF-K1 B variant strain was identified in a patient with African endemic Kaposi's sarcoma, who also had a B3/C2 class ORF 26 pattern. In 58.3% of iatrogenic Kaposi's sarcoma patients, a B5-type ORF 26 gene sequence pattern was identified. No association was found among particular subtypes, geographical origin of patients, or clinical presentation.

Genotypic analysis at multiple loci across Kaposi's sarcoma herpesvirus (KSHV) DNA molecules: clustering patterns, novel variants and chimerism

BACKGROUND

The genomes of human Kaposi's sarcoma-associated herpesvirus (KSHV) display several levels of DNA sequence heterogeneity and subgrouping that show distinctive clustering patterns in related human populations. The four major subtype patterns for the hypervariable ORF-K1 protein correlate closely with the principal diasporas resulting from the migration of modern humans out of East Africa and suggest that KSHV is an ancient human virus that is transmitted primarily in a familial fashion with consequent very low recombination rates. However, chimeric genomes have also been detected, especially with regard to the presence of P versus M alleles of the ORF-K15 gene.

OBJECTIVES

To understand further the genetic organization and evolutionary history of KSHV, especially with regard to possible new subtypes, recombinant genomes, constant region loci and clustering in particular ethnic groups or among classic versus epidemic cases in the same geographic area.

STUDY DESIGN

Direct PCR DNA sequencing was carried out on the ORF-K1 and ORF-K15 genes at the extreme left and right hand sides, as well as on six other internal loci of diagnostic samples collected from 70 new KSHV-positive patients in Israel, South Korea, Sicily, Scandinavia, Brazil, Uganda, South Africa and the US.

RESULTS AND CONCLUSIONS

Our overall results from more than 135 KSHV genomes from many different human population groups now provides evidence for seven distinct subtypes of KSHV genomes (referred to as A/P, B/P, C/P, D/P, M, N and Q). However, the two most closely related subtypes (A/P and C/P) are only differentiated at the LHS side of the genome, and the three most distantly related forms (M, N and Q) appear to exist only as small chimeric segments that are remnants from the RHS of more ancient forms of the virus. By analyzing multiple conserved loci across the B subtype genomes that predominate in sub-Saharan Africa, we can also now recognize three to four distinct B genome subgroups with varying patterns of inter and intratypic mosaicism. Analysis of classic KS genomes from Israel has revealed that the ORF-K1 clade referred to as A1' predominates in Ashkenazi Jewish immigrants from Russia, whereas C2 and C6 variants predominate in North African Sephardi Jews. A variety of chimeric genomes containing C2 or C3 ORF-K1 genes are disseminated among classic KS cases throughout Europe and Asia including Israel, Sicily, Scandinavia, South Korea, and Taiwan. Comparison of the genomes from classic versus AIDS-associated KSHV in the US indicates that it was derived originally by reactivation and spread of a subset of the endogenous viruses carried by descendants of immigrants from endemic areas of Northern and Eastern Europe, the Mediterranean and sub-Saharan Africa.

Recombination in human herpesvirus-8 strains from Uganda and evolution of the K15 gene

Human herpesvirus-8 (HHV-8) is believed to be the aetiological agent of Kaposi's sarcoma (KS). KS accounts for half the reported cancer cases in Uganda, and occurs in endemic and epidemic [human immunodeficiency virus (HIV)-associated] forms. We confirmed a high prevalence (74%) of HHV-8 antibodies in 114 HIV-negative Ugandan blood donors, and characterized the genomes of HHV-8 strains present in 30 adult Ugandan KS patients. Phylogenetic analysis of the uniquely variable K1 gene indicated that the majority of KS patients were infected by the B subtype of HHV-8, several by the A5 subtype, and one by a variant of the C subtype. Sequence analysis of nine strains at several other genome loci spaced out across the genome indicated that five are recombinants between subtypes when considered independently of previously published definitions of parental (unrecombined) genotypes. When previously published parental genotypes were taken into account, seven of the nine strains appeared to be recombinants. Analysis of the K15 gene, which exists in HHV-8 in two highly diverged alleles, indicated that the P allele predominates, with only a single strain bearing the M allele. Divergence between the M allele in the latter strain and that in the previously sequenced BC1 strain is at least as great as that between representatives of the P allele. This indicates that introduction of the M allele into extant HHV-8 subtypes did not occur by a single, relatively recent recombination event as was concluded from a previous study in which very limited variation in the M allele was reported.

Primary effusion lymphoma with herpesvirus 8 DNA in patients coinfected with HIV and hepatitis C virus: a report of 2 cases

The primary effusion lymphoma (PEL), commonly described in patients with AIDS, is a unique subset of diffuse large cell lymphoma in which the malignant lymphocytes proliferate exclusively in serous cavities. The cytologic, immunophenotypic, and molecular features of PEL are presented from findings of 2 patients coinfected with HIV and hepatitis C virus who presented with abdominal pain. Abdominal radiography in both patients displayed marked peritoneal effusions. Cytomorphologic examination of peritoneal fluid revealed a malignant lymphoma in both. Their immunophenotypic expression was CD30 (Ki-1) and epithelial membrane antigen. Molecular analysis demonstrated human herpesvirus 8 DNA in both patients and bcl-2 oncogene rearrangement within the major breakpoint region of t(14;18) chromosome translocation in Case B only. Clinical correlation supports the current concept that PEL represents a primary HIV/AIDS-related lymphoma in effusion. Cytomorphologic examination of body cavity fluid serves as a tool for the initial diagnosis of PEL.

Clinicopathologic study of Kaposi's sarcoma and strain analysis of human herpesvirus 8 (HHV-8) DNA in the Hua-Lien area of eastern Taiwan

BACKGROUND AND PURPOSE

Kaposi's sarcoma (KS) is a spindle cell malignancy of endothelial cell origin. The tumor has been demonstrated to be associated with human herpesvirus 8 (HHV-8) or Kaposi's sarcoma-associated herpesvirus-like virus (KSHV). Previous studies have revealed the distribution of unique viral strains in different ethnic populations. Eastern Taiwan has an ethnically mixed population with a relatively high incidence of KS. This study was designed to characterize the clinicopathologic features of KS and to evaluate the HHV-8 strain distribution in the Hua-Lien area of Eastern Taiwan.

METHODS

Clinical records and laboratory data were collected from 15 cases of KS diagnosed and treated between 1993 and 1999 in Tzu-Chi General Hospital. For nine cases, paraffin blocks were available for the molecular study of HHV-8. HHV-8 genomic variation was analyzed using polymerase chain reaction nucleotide sequencing of ORF26 and ORF75 of HHV-8 genomes derived from different subgroups of KS.

RESULTS

Among the 15 patients with KS, two had AIDS-associated disease, four had gouty arthritis and psoriasis and were receiving corticosteroid therapy (iatrogenic type), and nine had classical KS. Nine of the 15 cases occurred in aborigines, including one with AIDS-associated disease, four with iatrogenic disease, and four with classical disease. Among the nine cases for which tissue was available for DNA analysis, eight were positive for HHV-8 DNA. Sequence analysis revealed that the C strain occurred in three Han Chinese KS patients, whereas a hitherto rarely described strain (strain D) occurred in all four aborigines tested (including one with AIDS-associated KS) and one Han Chinese with AIDS from Burma.

CONCLUSION

This study found a high proportion of iatrogenic KS and the finding of a rarely described strain D virus in Eastern Taiwan aborigines. Our studies further confirm the distribution of different types of KS and virus strains in different ethnic populations.

Molecular characterization of strains of Human herpesvirus 8 from Japan, Argentina and Kuwait

Current genotyping systems for Human herpesvirus 8 (HHV-8) are based on the highly variable gene encoding the K1 glycoprotein. Most strains collected worldwide cluster into two subtypes (I/A and II/C). Sequenced African strains have belonged to subtypes I/A and IV/B. Members of all three of these subtypes can have either the M or P allele at the right-hand side (RHS) of the genome. Strains obtained predominantly from aboriginal or relatively isolated populations have formed clades that branch at a distance from subtypes I/A and II/C, all being of the RHS P allele. The characterization is reported here of 16 Japanese, two Kuwaiti and five Argentine HHV-8 strains obtained from human immunodeficiency virus-infected and non-infected patients with Kaposi's sarcoma (KS), primary effusion lymphoma, multicentric Castleman's disease or renal transplants. K1 sequences of five Japanese, one Kuwaiti and two Argentine strains were identified as subtype I/A and eight Japanese, one Kuwaiti and three Argentine strains were subtype II/C. Three strains from elderly classic KS patients originally from Hokkaido, a northern Japanese island, were relatively closely related to strains of subtypes III/D and E. Consistent with previous observations, both the M and P alleles were identified at the RHS of subgroup I/A and II/C genomes; only the P allele was detected among the three Hokkaido strains. Distances among the Hokkaido strains were similar to the distance between subtypes I/A and II/C, suggesting that the Hokkaido strains may represent two distinct subtypes and that, as more strains are analysed, the currently recognized III/D subgroups will probably emerge as independent subtypes.

Distinct distribution of rare US genotypes of Kaposi's sarcoma-associated herpesvirus (KSHV) in South Texas: implications for KSHV epidemiology

Genotypes of Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) from patients with KS in South Texas were examined. Open-reading frame (ORF)-K1 and ORF-K15 DNA segments from 16 KSHV isolates were amplified by polymerase chain reaction, and KSHV subtypes were assigned on the basis of sequence variations. K1 genotyping showed that 75% exhibited C subtype and 25% exhibited A subtype. K15 genotyping showed that 56% exhibited M form, of which 89% exhibited C3 K1 subtype and 44% exhibited P form. A unique isolate was found and was classified as C6 clade. All of the M KSHV isolates had been obtained from human immunodeficiency virus-negative classic KS patients >50 years of age, of whom 78% were Hispanic. Conversely, all KS patients with AIDS were <36 years of age and exhibited P form KSHV. These findings indicate that C3/M KSHV genotypes are more prevalent in South Texas (50%) than in other US regions (3%) and that M form KSHV likely existed in this region long before the AIDS epidemic.

Molecular epidemiology of human herpesvirus 8 in africa: both B and A5 K1 genotypes, as well as the M and P genotypes of K14.1/K15 loci, are frequent and widespread

We have studied 52 new HHV8 strains by sequencing the complete hypervariable K1 gene and genotyping the K14.1/K15 loci located at both sides, respectively, of the viral genome. The samples originated from 49 patients with Kaposi's sarcoma (KS; 32 patients), multicentric Castleman's disease (MCD; 12 patients), or primary effusion lymphoma (PEL; 5 patients). Among these patients, 32 were of African origin (West and Central African countries and Creoles from French Guiana) and the 17 others were mostly French homosexuals. Comprehensive phylogenetic studies allowed the identification of distinct groups within the three already known main subtypes. Interestingly, two new sequences that did not cluster within a known subtype or group could be considered as prototypes of early/ancient variants of the C subtype and A/C set, respectively. Among the 32 African strains, the majority were either of the B subtype (13 cases) or of the A5 group (11 cases), indicating that this latter genotype is frequent and widespread in Africa. In contrast, a subtype C strain infected most of the 17 other patients. PCR-based genotyping of the K14.1/K15 loci revealed an overall predominance of P subtype, except in the A5 and B K1 groups, in which the P and M alleles were equally represented. The implications of these data on the evolution and spread of HHV8 among human African populations are discussed.

Lytic growth of human herpesvirus 8: morphological aspects

The human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus, is a gamma herpesvirus associated with AIDS-related body cavity-based lymphomas (BCBL), also called primary effusion lymphomas (PEL). These are a rare form of non-Hodgkin lymphomas in which HHV-8 is present, often associated with Epstein-Barr virus (EBV) infection. HHV-8 is also present in a latent state or in a state of low-level persistence in different primary effusion lymphoma-derived cell lines, such BCBL-1 cells, that lack EBV infection. This cell line was induced to produce mature virions by treatment with 12-O-tetradecanoyl phorbol-13-acetate (TPA) and the characteristic ultrastructural features of HHV-8 lytic replication were identified and compared to those of the other members of Herpesviridae family.