Evelyne T. Lennette

Antibodies to human herpesvirus type 8 in the general population and in Kaposi's sarcoma patients

BACKGROUND Much of the evidence that human herpesvirus type 8 (HHV-8) is associated with Kaposis sarcoma (KS) has come from molecular studies of HHV-8 DNA. Seroepidemiological studies have been hampered by the lack of a reliable assay. METHODS The serological data reported here were obtained by means of a mouse monoclonal antibody-enhanced immunofluorescence assay for antibodies to lytic and latent HHV-8 antigens. 1435 single samples of serum (or plasma) from many different disease groups and parts of the world were assayed. FINDINGS All patients with African endemic KS and 96% of American patients with AIDS-associated KS were seropositive for lytic antigen, as were 90% of American HIV-infected homosexual men; by contrast only 23% of HIV-seropositive drug users and 21% of HIV-seropositive women were positive for HHV-8 antibody. Factor VIII treatment before 1983 did not increase the risk of HHV-8 infection in patients with haemophilia. In the American general population, about 25% of adults (including volunteer blood donors) and 2-8% of children had antibodies to HHV-8. INTERPRETATION Our data are consistent with HHV-8 being primarily associated with sexual transmission, but the HHV-8 seropositivity rate in American children suggests that there is a non-sexual route of HHV-8 infection also. On the evidence available so far, the risk of parenteral transmission is low.

Chronic fatigue syndrome: clinical condition associated with immune activation

There is much conflicting immunological and viral data about the causes of chronic fatigue syndrome (CFS); some findings support the notion that CFS may be due to one or more immune disorders that have resulted from exposure to an infectious agent. In the present study, flow cytometry and several different monoclonal antibodies recognising T, B, and natural killer (NK) cell populations as well as activation and cell adhesion antigens were used to study 147 individuals with CFS. Compared with healthy controls, a reduced CD8 suppressor cell population and increased activation markers (CD38, HLA-DR) on CD8 cells were found. The differences were significant (p = 0.01) in patient with major symptoms of the disease. These immunological indices were not observed in 80 healthy individuals, in 22 contacts of CFS patients, or in 43 patients with other diseases. No correlation of these findings in CFS patients with any known human viruses could be detected by serology. The findings suggest that immune activation is associated with many cases of CFS.

Frequent isolation of HHV-6 from saliva and high seroprevalence of the virus in the population

Human herpesvirus-6 (HHV-6) was recovered at high frequency (greater than 85%) from the saliva of both healthy individuals and those infected with the human immunodeficiency virus (HIV). The level of isolation mirrored the high prevalence of antibodies to HHV-6 found in sera obtained from residents of diverse areas of the world. Seroconversion occurred between 1 and 3 years of age; seroprevalence ranged between 80% and 100% among adults under 40 and decreased to 35% between ages 62 and 88. Serum titres in healthy individuals remained stable during periods of virus shedding. Immune cellular dysfunction in patients was associated with high geometric mean HHV-6 antibody titres. These observations suggest that HHV-6 infection takes place within the first 3 years of life, and strongly implicate oral shedding as a common means of transmission of this newly described herpesvirus.

Infectious human herpesvirus 8 in a healthy North American blood donor

BACKGROUND Molecular studies have provided strong evidence for the association of human herpesvirus 8 (HHV-8) with Kaposis sarcoma. These data have been supported by serological studies, which have also suggested that HHV-8 can be found in the healthy population. We report the presence of infectious HHV-8 in a healthy donor to a North American blood bank. METHODS We examined the peripheral blood mononuclear cells or CD19 cells of blood donors by PCR for evidence of HHV-8 infection. The CD19 cells were separated from peripheral blood mononuclear cells by immunomagnetic-bead selection. To enhance detection of HHV-8, the CD19 cells from eleven unsystematically selected blood donors were activated with phorbol ester and recombinant interleukin-6; the culture fluid was filtered and inoculated onto HHV-8-negative target CD19 cells that had been prepared from phytohaemagglutinin-stimulated peripheral blood mononuclear cells. These inoculated target cells were cultured for 3 days and then analysed for HHV-8 sequences by PCR. Serum samples were tested for antibodies to HHV-8 by an indirect immunofluorescence assay. FINDINGS One blood donor was consistently found to be infected with HHV-8 by PCR after the cell-culture activation procedure. He was seropositive for the virus. The HHV-8 recovered was infectious, as shown by a reverse-transcription-PCR technique that detected HHV-8 RNA in the inoculated target cells. INTERPRETATION These data provide the first indication that HHV-8 can be recovered from the blood of a healthy individual, a blood donor, and that the virus is infectious. This observation suggests that HHV-8 could be transmitted by blood transfusion, a possibility that merits further study.

Interassay Correlation of Human Herpesvirus 8 Serologic Tests

To standardize human herpesvirus 8 (HHV-8) antibody assays for application to asymptomatic infection, a blinded comparison was done of seven immunofluorescence assays and ELISAs. Five experienced laboratories tested a serum panel from 143 subjects in 4 diagnostic groups. Except for a minor capsid protein ELISA, the other six tests detected HHV-8 antibodies most frequently in classic (80%-100%) and AIDS-related (67%-91%) Kaposis sarcoma, followed by human immunodeficiency virus-seropositive patients (27%-60%), and least frequently in healthy blood donors (0-29%). However, these six assays frequently disagreed on individual sera, particularly for blood donor samples. Current HHV-8 antibody tests have uncertain accuracy in asymptomatic HHV-8 infection and may require correlation with viral protein or nucleic acid detection. Antibody assays are useful for epidemiologic investigations, but the absolute prevalence of HHV-8 infection in the United States cannot yet be determined.

Human herpesvirus 8 detection in nasal secretions and saliva

The presence of human herpesvirus 8 (HHV-8) was determined by polymerase chain reaction (PCR) in nasal secretions and saliva from 14 HHV-8-seropositive persons, including 8 Kaposis sarcoma patients: 7 were human immunodeficiency virus type 1-infected, 6 of whom were asymptomatic. HHV-8 was detected in one or both body fluids in 8 (57%) of 14 subjects. Parallel PCR testing revealed the concomitant presence of cytomegalovirus, Epstein-Barr virus, and HHV-6 in various combinations in these body fluids. These data indicate frequent shedding of multiple herpesviruses in nasal secretions and saliva, particularly in Kaposis sarcoma patients. Both body fluids are therefore potential sources HHV-8 by nonsexual transmission.

Prevalence and determinants of anti‐lytic and anti‐latent antibodies to human herpesvirus‐8 among Italian individuals at risk of sexually and parenterally transmitted infections

Three hundred seventy‐nine individuals [137 non‐injecting drug using (non‐IDU) heterosexuals, 130 homosexual men and 112 IDU] attending the human immunodeficiency virus (HIV) testing program of a sexually transmitted disease (STD) clinic in Rome were studied to estimate the prevalence and to identify the modalities of transmission of human herpesvirus‐8 (HHV‐8) infection. Serological analysis was performed by using an immunofluorescence assay able to detect anti‐latent and anti‐lytic HHV‐8 antibodies. Twelve acquired immunodeficiency syndrome (AIDS)‐Kaposis sarcoma (KS) patients and 94 blood donors were tested as reference population groups. Anti‐lytic antibodies were detected in 185 (48.8%) individuals; 52 of them (13.7%) also had anti‐latent antibodies. Both anti‐lytic and anti‐latent antibody prevalence were higher among homosexual men (66.9% and 27.7%, respectively) than among IDU (49.1% and 8.0%, respectively) and non‐IDU heterosexuals (31.4% and 5.1%, respectively), and tended to increase with age. Anti‐lytic HHV‐8 antibodies were associated with syphilis [odds ratio (OR) = 3.81] but not with hepatitis C virus (HCV) seropositivity. HIV‐infected homosexual men were more likely to have HHV‐8 antibodies than those who were HIV‐negative. When using anti‐latent antibodies the direction of the OR remained the same, although the associations did not often reach statistical significance. Among AIDS‐KS patients, 83.3% had anti‐lytic and 66.6% had anti‐latent antibodies. Among blood donors, 28% had anti‐lytic antibodies and 2 of them (2.1%) also had anti‐latent antibodies. Our data indicate that HHV‐8 seroprevalence increases with age and is higher among homosexual men, particularly those infected with HIV. This is consistent with sexual transmission of HHV‐8 infection. In addition, the presence of HHV‐8 antibodies in HIV‐negative non‐IDU heterosexual contacts and in healthy blood donors is consistent with the high incidence of classic KS in Italy. Int. J. Cancer. 77:361–365, 1998.

The restricted cellular host range of human herpesvirus 8

DesignA selection of primary and transformed cell types were evaluated for their susceptibility to infection with human herpesvirus 8 (HHV-8)/Kaposis sarcoma- associated herpesvirus. MethodsSources of HHV-8 included Kaposis sarcoma lesion punch biopsies that were either cocultured directly with target cells or that were first cocultured with human lymphocytes to derive HHV-8-containing fluids that were inoculated onto target cells. HHV-8 was also obtained from primary effusion lymphoma-derived cell lines. Techniques to detect infection included the PCR, immunofluorescence assays and in situ hybridization. ResultsSusceptible cells included human umbilical cord blood mononuclear cells (UCMC), adult CD19 B cells, macrophages and certain endothelial cells of human and animal origin, including some that are transformed with human papilloma virus type 16 E6 and E7 genes. The infection of lymphocytes did not yield established lymphoblastoid cell lines (LCL) and virus infection persisted for only 4–7 days. However, long-term HHV-8 infection of UCMC could be achieved by coinfection with Epstein–Barr virus. HHV-8 could also infect UCMC LCL recently derived by Epstein–Barr virus transformation, but long-established LCL could not be infected with HHV-8. ConclusionsThese data provide further biological evidence in cell culture for the limited cellular host range of HHV-8 to CD19 B cells, macrophages, and certain endothelial cells.

Recurrent aphthous ulcers in association with HIV infection: Description of ulcer types and analysis of T-lymphocyte subsets

This study was conducted to characterize the recurrent aphthous ulcers (RAU) found in association with human immunodeficiency virus (HIV) infection, to examine evidence for increased severity of the ulcers with HIV disease, and to determine whether increased severity is associated with abnormalities of peripheral blood lymphocyte subsets. Seventy-five HIV-seropositive patients with RAU were followed for up to 2 years, and lymphocyte subsets were analyzed in 42. Minor, herpetiform, and major ulcer types were seen, but unexpectedly, 66% of the patients had the usually uncommon herpetiform and major types. These types were temporally associated with symptomatic HIV disease. Patients with major RAU were significantly more immunosuppressed than those with minor or herpetiform RAU in that they had fewer CD4 and CD8 lymphocytes (p less than 0.05). The lesion of RAU is considered to represent a local breakdown in immunoregulation. The systemic immune imbalance seen with HIV disease may amplify the local defect and lead to more severe ulcers.

Increased human herpesvirus 8 seroprevalence in young homosexual men who have multiple sex contacts with different partners.

The objective of this study was to evaluate the behavioral risks that are associated with human herpesvirus 8 (HHV-8) infection in a cohort of young homosexual men. Seventy-nine subjects (ages 22-33 years) who completed a questionnaire about their sexual and drug use behavior over the preceding year were recruited from the San Francisco Young Mens Health Study. Plasma samples were tested for anti-HHV-8 antibodies using an indirect IFA. Thirty-eight subjects (48.1%) were infected with HHV-8. HHV-8 infection was significantly linked to an increasing number of male sex partners (P=.025, Mantel-Haenszel chi2 test for trend), suggesting a strong association between HHV-8 infection and multiple homosexual contacts.