Search

Objective: To examine the association between Kaposi's sarcoma (KS), human herpes virus 8 (HHV8) and AIDS dementia complex (ADC)., Design: A total of 599 HIV-1 infected homosexual men participated in a prospective cohort study (Amsterdam, 1984-1996)., Methods: The risk for ADC in patients with prior KS or HHV8 infection was estimated using the Cox proportional hazards method with adjustments for antiretroviral medication and low CD4 cell counts., Results: Of the 599 participants, 290 (48.4%) had HHV8 antibodies, 99 (16.5%) had KS and 30 (5.0%) had ADC. ADC was diagnosed in 5.2% of participants with KS and 5.0% of those without KS, and in 4.8% of HHV8 seropositive compared to 5.2% seronegative individuals and thus was not associated with KS or HHV8 infection. Using a time-dependent Cox proportional hazards analysis with the date of KS as risk factor, the risk for ADC was 2.7 [95% confidence interval (CI), 0.92-7.96; P = 0.07) and when only definite ADC was considered it was 3.5 (95% CI, 1.00-12.26;P = 0.05). After adjusting for decreases in CD4 cell count and use of medication, the hazards ratio for participants with KS to develop ADC was 2.0 (95% CI, 0.66-5.77; P = 0.23) and 2.6 (95% CI, 0.73-9.12; P = 0.14), respectively. HHV8 seropositivity, adjusted for the same variables, showed a risk for ADC of 0.85 (95% CI, 0.41-1.77;P = 0.66) and for definite ADC 0.69 (95% CI, 0.27-1.73; P = 0.42). The expected neuroprotective effects of antiretroviral medication were observed., Conclusions: KS or HHV8 does not significantly influence the risk for developing ADC in a group with a uniform risk for developing KS therefore we recommend caution in searching for a KS-associated or HHV8-derived therapy for ADC.

Objective: To look for a virus related to Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) in chimpanzees and to investigate phylogenetic and biological similarities to KSHV., Methods: Peripheral blood mononuclear cell (PBMC) DNA samples from chimpanzees (Pan troglodytes troglodytes) were screened with newly designed consensus oligonucleotide primers for the DNA polymerase gene of KSHV-related gamma2-herpesviruses (rhadinoviruses). Samples from HIV-1-infected and -uninfected chimpanzees were screened with virus-specific primers. Antibodies to KSHV structural and latent antigens were measured by immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and Western blot., Results: We identified 972 base pairs (bp) of a new viral DNA polymerase sequence with 81.6% (nucleotides) and 93.2% (protein) identity to that of KSHV/HHV8. It was detected in 15/37 (41%) animals experimentally infected with HIV-1, but only in one out of 30 uninfected animals (P<0.001). Antibodies were found by immunofluorescence to structural, but not latent, KSHV antigens in nearly all HIV-1-infected and uninfected animals., Conclusion: Like man and two other Old World primate species, chimpanzees harbour a virus closely related to KSHV/HHV8, termed Pan troglodytes rhadinovirus-1 (PtRV-1). Like KSHV, PtRV-1 is more easily detected by polymerase chain reaction (PCR) in the PBMC of HIV-1-infected than of HIV-1-uninfected individuals, suggesting increased viral load. Despite the close phylogenetic relationship and biological similarities between KSHV and PtRV-1, Kaposi's sarcoma (KS) has not been reported in HIV-1-infected chimpanzees. PtRV-1 may lack some of the pathogenic determinants of KSHV, or humans and chimpanzees may differ in how they control the infection with their respective rhadinoviruses.

Objective: To study the evolution of Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus type 8 in Europe and Africa., Design and Methods: PCR and sequence analysis of the variable viral membrane glycoprotein gene K1 in 58 tumour and peripheral blood samples from patients with AIDS-related Kaposi's sarcoma (KS), 'classic' (HIV-negative) KS, transplant KS, Multicentric Castleman's Disease, other lymphoproliferative disorders, and healthy KSHV-infected individuals from the UK, Denmark, Sweden, Italy, Spain, Iceland, The Faroe Islands, Greece, The Gambia and Uganda., Results: Three major groups of K1 sequences were found: A, B and C, as defined previously. The K1 gene has evolved, both within and between these three groups, under positive selection. KSHV group B strains predominate in Africa and are more distant from groups A and C, found in Europe, than A and C are from each other. Within group C two subgroups, C' and C", can be identified. Subgroup C" is more closely related to group A in a region of the K1 protein and appears to be phylogenetically close to the branchpoint between A and C. Group A and C strains are currently found in both HIV-1-infected and -uninfected Europeans, and were already present in Europe before the start of the AIDS epidemic. We found some examples of closely related K1 sequences in Italy and Denmark, but in general KSHV strains in Europe did not cluster geographically., Conclusion: KSHV strains in East and West Africa are closely related but phylogenetically distant from those in Europe. The two major KSHV groups in Europe are more closely related, with some strains adopting an intermediate phylogenetic position. In Europe, KSHV strains may have been disseminated at least several decades ago. Variability in the K1 region is driven by selection and does not correlate with different KSHV-related pathologies or geographic regions where clinically more aggressive HIV-negative KS ('endemic' KS) is more common.

Background: The finding of antibodies against human herpesvirus 8 (HHV-8) is associated with the occurrence of Kaposi's sarcoma in persons infected with HIV. However, the predictive value of HHV-8 antibodies for Kaposi's sarcoma in HIV infection is unknown., Methods: The Amsterdam Cohort Studies on HIV infection and AIDS started in 1984 for homosexual men and in 1985 for injecting drug users. Serum samples from 1459 homosexual men and 1167 drug users were tested for antibodies to recombinant HHV-8 lytic-phase capsid (ORF65) antigen and latent-phase nuclear (ORF73) antigen. Individuals were retrospectively identified as HHV-8-positive or HHV-8-negative at enrolment or HHV-8 seroconverter during the study. Kaposi's sarcoma-free survival time was compared between HIV-infected men who were positive for HHV-8 at enrolment and those who later seroconverted for HHV-8. Hazard ratios were estimated for Kaposi's sarcoma, lymphoma, and opportunistic infection according to the HHV-8 serostatus., Results: The incidence of HHV-8 seroconversion among drugs users was 0.7 per 100 person-years based on 31 seroconversions, whereas an incidence of 3.6 was found among homosexual men based on 215 seroconversions. The hazard ratio for Kaposi's sarcoma was 3.15 (95% CI: 1.89-5.25) in HIV-infected individuals if HHV-8 antibodies were present either at enrolment or at HIV seroconversion. In HIV-infected persons who later seroconverted to HHV-8, Kaposi's sarcoma developed more rapidly: hazard ratio of 5.04 (95% CI: 2.94-8.64), an additional risk of 1.60 (95% CI: 1.01-2.53; P = 0.04). Time-dependent adjustment for CD4+ cell count and HIV RNA had no impact on the additional risk, although the CD4+ cell count was an independent risk factor for Kaposi's sarcoma. HHV-8 infection did not increase the risk of AIDS-related lymphoma or opportunistic infections., Conclusions: The incidence of HHV-8 infection is higher in homosexual men than in drug users. The presence of HHV-8 antibodies in HIV-infected persons increases the risk of Kaposi's sarcoma. Among HIV-infected persons, those who subsequently seroconvert for HHV-8 are at highest risk. These results strongly confirm the causal role of HHV-8 in Kaposi's sarcoma and emphasize the clinical relevance of HHV-8 seroconversion before and after the HIV infection.

Objective: To ascertain the prevalence of Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus (HHV) type 8, and cytomegalovirus (CMV) DNA in semen was investigated., Methods: Amplification by nested polymerase chain reaction was used to detect viral DNA sequences in samples from 24 HIV-infected gay men, 15 of them with Kaposi's sarcoma (KS), and 115 healthy donors., Results: Six of the 24 HIV-infected patients had detectable HHV-8 DNA in their semen: three of the 15 patients with KS and three of the nine patients without KS. CMV DNA was detected in 20 semen samples from HIV-infected patients. None of the semen samples from healthy donors had detectable HHV-8 DNA and rates of CMV DNA detection were low (3%)., Conclusions: The study demonstrates the presence of HHV-8 in semen from HIV-infected individuals with, or at risk, of developing KS and the potential for sexual transmission of the virus. We found no evidence of HHV-8 in the semen of HIV-uninfected donors.

Objective: To characterize putative binding sites for HIV-1 gp41 to H9 cells., Design: Based on accumulating evidence in the literature that HIV-1 can bind to cell surfaces independent of CD4, we attempted to clarify whether gp41, the transmembrane HIV-1 protein, contributes to CD4-independent binding. We therefore tested binding of gp41 to cells., Methods: Using fluorescence-activated cell-sorter analysis, we examined the binding of recombinant gp160 (gp160) and soluble gp41 (sgp41; Env amino acids 539-684) to H9 cells, and located the putative binding site(s) of gp41 by inhibition using 16 HIV-1 Env peptides. Putative HIV-1 receptor proteins in H9 cell lysates were Western blotted and precipitated using sgp41., Results: sgp41 bound to the CD4+ H9 cells and rgp160 bound to H9 cells independent of gp120-binding sites on CD4 molecules. Two gp41 peptides (Env amino acids 591-605 and 651-665) inhibited the binding of sgp41 to H9 cells. Four bands, of 37, 40, 55 and 97 kD, were blotted in H9 cell lysates, and three bands, 40, 97 and 108 kD, were observed in the precipitation analysis using lysates of 125I-surface-labelled H9 cells and sgp41 attached to sepharose beads., Conclusions: HIV-1 gp41 contains two putative binding sites to H9 cells. These sites may be located within Env amino acids 591-605 (ERYLKDQQLLGIWGC) and 651-665 (TLLEESQNQQEKNEQ). Using two different techniques, five proteins (37, 40, 55, 97 and 108 kD) were identified in H9 lysates as possible candidates for gp41 binding.

We produced recombinant envelope-derived peptides of HIV-2 for use in a diagnostic enzyme-linked immunosorbent assay (ELISA) or Western blot by expressing several restriction enzyme fragments from the env gene of HIV-2 in the bacterial fusion vector pEX-3. On Western blots, 17 out of 18 anti-HIV-2-positive sera available to us reacted strongly with those recombinant peptides which were derived from, or extended into, the transmembrane protein of HIV-2. In contrast, recombinant peptides derived from the external envelope glycoprotein were only weakly recognized by two sera. We observed a cross-reactivity of some human sera containing antibodies to HIV-1 with the HIV-2 peptides derived from the transmembrane protein of HIV-2. In spite of this cross-reactivity, a serological distinction between anti-sera to HIV-1 and HIV-2 can be attempted by simultaneous testing in ELISA on recombinant peptides derived from the transmembrane protein of HIV-1 and HIV-2.