Comparative evaluation of three serological methods for detection of human herpesvirus 8-specific antibodies in Canadian allogeneic stem cell transplant recipients

Similar Viral and Immune Characteristics of Kaposi Sarcoma in ART-treated People Living With HIV and Older Patients With Classic Kaposi Sarcoma

Background

Reemergence of human herpesvirus 8 (HHV-8)-induced Kaposi sarcoma (KS) in people living with HIV (PLWH) despite antiretroviral therapy (ART) poses a clinical challenge because they already have favorable CD4 T-cell numbers and undetectable viral loads. We observed that clinical presentation in PLWH on ART resembled classic KS found in older HIV-uninfected patients and hypothesized that immunosenescence may thus play a role in occurrence of KS on ART. We compared viral and immune factors implicated in the development of KS in ART-treated PLWH (HIV KS) and HIV-uninfected classic KS patients (cKS), compared to controls without KS (HIV Control, cControls respectively).

Methods

Plasma, peripheral blood mononuclear cell, and skin tissues were obtained from 11 HIV KS and 11 cKS patients and 2 groups of age-matched controls.

Results

HIV KS participants were younger than cKS (aged 53 vs 75 years). HHV-8 genotypes did not differ between groups. Despite the younger age and a lower CD4/CD8 ratio, activated, exhausted, and senescent T-cell frequencies were similar between HIV KS and cKS. Anti-HHV-8 immunoglobulin G levels were higher and circulating HHV-8 DNA lower in HIV KS compared with cKS. Circulating platelet-derived growth factors AA-BB and granulocyte colony-stimulating factors were higher in HIV KS We observed similar levels of HHV-8 DNA and PD-1 expression in skin lesions from HIV KS and cKS patients.

Conclusions

Altogether, early immune senescence could be involved in the development of KS in ART-treated PLWH. Higher anti-HHV-8 immunoglobulin G levels could be linked with lower circulating viral load. Such insights should help developing therapeutical strategies to prevent development and treat KS in PLWH on ART.

Herpes Virus Infections Other than Cytomegalovirus in the Recipients of Hematopoietic Stem Cell Transplantation

This review discusses the epidemiologic and clinical aspects of herpes viruses other than cytomegalovirus in patients who have undergone hematopoietic stem cell transplantation.

A high seroprevalence of human herpesvirus type 8 already present in patients with chronic hepatitis before the development of cirrhosis

A high seroprevalence of human herpesvirus type 8 (HHV-8) in mild cirrhotics is significantly associated with hepatitis activity. Cirrhosis is always derived from chronic hepatitis. We aimed to evaluate the prevalence of HHV-8 infection in patients with chronic hepatitis. Blood samples collected from 129 patients with chronic hepatitis and 129 age- and sex-matched healthy controls were analysed for monocyte and platelet counts, hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV), HHV-8 antibody and DNA, and alanine aminotransferase (ALT). Mean monocyte and platelet counts were significantly higher and lower in patients than in healthy controls (p = 0.02 and < 0.0001, respectively). Seropositive rate for HHV-8 antibodies was significantly greater in patients (32.6%) than in controls (20.9%, p = 0.04), particularly in patients with HCV infection, or higher plasma ALT levels, or both (p = 0.004, 0.01, and 0.0009, respectively). Antibody titres for HHV-8 in patients also exceeded those in controls (p = 0.02). The mean age of HHV-8 seropositive patients (60.3 years) was significantly older than that of seronegatives (52.3 years) (p = 0.0007). Patients aged 55 or older had higher seropositive rate and titres for HHV-8 antibodies than those younger (p = 0.005 and 0.007, respectively). A significantly high HHV-8 seroprevalence is already present in patients with chronic hepatitis before the development of cirrhosis, particularly in patients with HCV infection and/or higher plasma ALT levels. Advancing age seems to play an important role in HHV-8 seroprevalence in patients with chronic hepatitis.

Fulminant anaplastic large cell lymphoma (ALCL) concomitant with primary cytomegalovirus (CMV) infection, and human herpes virus 8 (HHV-8) infection together with Epstein-Barr-virus (EBV) reactivation in a patient with asymptomatic HIV-infection

Background

Most malignant lymphomas in HIV-patients are caused by reactivation of EBV-infection. Some lymphomas have a very rapid fulminant course. HHV-8 has also been reported to be a cause of lymphoma. The role of CMV in the development of lymphoma is not clear, though both CMV and HHV-8 have been reported in tissues adjacent to the tumour in Burkitt lymphoma patients. Here we present a patient with asymptomatic HIV infection, that contracted a primary cytomegalovirus (CMV) infection and human herpes virus 8 (HHV-8) infection. Three weeks before onset of symptoms the patient had unprotected sex which could be possible source of his CMV and also HHV-8 infection He deteriorated rapidly and died with a generalized anaplastic large cell lymphoma (ALCL).

Methods

A Caucasian homosexual male with asymptomatic human immunodeficiency virus (HIV) infection contracted a primary cytomegalovirus (CMV) infection and human herpes virus 8 (HHV-8) infection. He deteriorated rapidly and died with a generalized anaplastic large cell lymphoma (ALCL). Clinical and laboratory records were compiled. Immunohistochemistry was performed on lymphoid tissues, a liver biopsy, a bone marrow aspirate and the spleen during the illness and at autopsy. Serology and PCR for HIV, CMV, EBV, HHV-1–3 and 6–8 was performed on blood drawn during the course of disease.

Results

The patient presented with an acute primary CMV infection. Biopsies taken 2 weeks before death showed a small focus of ALCL in one lymph node of the neck. Autopsy demonstrated a massive infiltration of ALCL in lymph nodes, liver, spleen and bone marrow. Blood samples confirmed primary CMV- infection, a HHV-8 infection together with reactivation of Epstein- Barr-virus (EBV).

Conclusion

Primary CMV-infection and concomitant HHV-8 infection correlated with reactivation of EBV. We propose that these two viruses influenced the development and progression of the lymphoma. Quantitative PCR blood analysis for EBV, CMV and HHV-8 could be valuable in diagnosis and treatment of this type of very rapidly developing lymphoma. It is also a reminder of the importance of prevention and prophylaxis of several infections by having protected sex.

High prevalence of human herpesvirus type 8 infection in patients with pulmonary tuberculosis in Taiwan

Blood samples were collected from 101 untreated pulmonary tuberculosis (TB) patients and 101 age- and sex-matched healthy control subjects. TB patients had lower lymphocyte and a higher monocyte counts than control subjects (p <0.0001 for both). The seropositive rate of human herpesvirus (HHV) type 8 antibody was higher in patients (30/101) than in control subjects (15/101) (p = 0.01). Antibody titres in patients also exceeded those in control subjects (p 0.006). Lymphocyte and monocyte counts between seronegative and seropositive subjects were not different. Four patients were positive for HHV-8 DNA. The study revealed a significantly higher HHV-8 seroprevalence in untreated pulmonary TB patients than in general population.

Development of whole-virus multiplex luminex-based serological assays for diagnosis of infections with kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 homologs in macaques

Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 is a tumorigenic rhadinovirus that is associated with all forms of Kaposi's sarcoma. Current serological detection of KSHV is based on enzyme-linked immunosorbent or immunofluorescence assays that suffer from a variety of problems, including the lack of defined standards for test comparison. While KSHV is the only known human rhadinovirus, two lineages of KSHV-like rhadinoviruses are found in Old World primates: the RV1 lineage includes KSHV and retroperitoneal fibromatosis herpesvirus (RFHV) in macaques, and the RV2 lineage includes RRV and MneRV2 from different macaque species. To develop animal models of KSHV-associated diseases, we developed quantitative multiplex bead-based serological assays to detect antibodies against rhadinovirus antigens. Proteins from KSHV (RV1) and MneRV2 (RV2) virions were coupled to spectrally distinct fluorescent beads and used in Luminex flow cytometry-based assays to detect immune responses in macaques. Both assays showed large dynamic ranges with high levels of seroreactivity to both KSHV and MneRV2 proteins. A large set of macaque serum samples from the Washington National Primate Research Center was screened, and most of the samples (82%) were positive in both assays, consistent with the high level of RV1-RV2 coinfection detected by PCR. The macaque sera showed broad, variable, and unique serological responses to the different viral antigens, allowing an initial seroprevalence to be determined for the macaque viruses. The Luminex assays offer a novel multiplexed approach to assess rhadinovirus infection patterns in both humans and nonhuman primates. This will help advance our understanding of rhadinovirus biology and associated host immunological responses.

Human herpesvirus 8 genomes and seroprevalence in United States blood donors

BACKGROUND

Human herpesvirus 8 (HHV-8) is a gamma-herpesvirus that causes Kaposi's sarcoma. The prevalence of HHV-8 genomes in US blood donors has not been systemically studied.

STUDY DESIGN AND METHODS

A sensitive and quantitative real-time polymerase chain reaction (PCR) assay was used to detect HHV-8 DNA from purified CD19+ B lymphocytes from randomly selected US whole blood donors. Cellular target for the GAPDH gene was used to quantify cell-equivalent DNA. HHV-8 PCR was run in duplicate for each donor specimen along with an HHV-8 genomic copy standard. HHV-8 antibodies were detected by an indirect immunofluorescence assay.

RESULTS

Specimens were obtained from 962 blood donors. DNA from more than 3 x 10(5) B-cell equivalents were obtained from 684 donors. No HHV-8 DNA was detected from any of the blood donor specimens. For the 684 donors, HHV-8 genomes were not detected in the DNA equivalent of 3 x 10(5) to 6 x 10(5) CD19+ B cells with real-time PCR, which has a detection limit of eight copies (95% confidence interval, 0-3/684). Negative results from the remaining 220 donors were potentially confounded by insufficient input DNA into the PCR procedures. Antibodies to HHV-8 were detected in 7.3% (70/962) of the donors. HHV-8 genomes were not detected from 40 of 70 HHV-8-seropositive donor B-cell DNA samples.

CONCLUSION

The results indicate that the prevalence of detectable HHV-8 genomes in healthy blood donors is very low.

Development of an immunofluorescence assay using recombinant proteins expressed in insect cells to screen and confirm presence of human herpesvirus 8-specific antibodies

Human herpesvirus 8 (HHV-8), or Kaposi's sarcoma (KS)-associated herpesvirus, has been linked to all forms of KS. The results of most current serological assays for the detection of HHV-8-specific antibodies have low levels of concordance among themselves. To establish a sensitive and specific testing strategy that can be used to screen for HHV-8-specific antibodies, three HHV-8 proteins, ORF65, ORF73, and K8.1A, were expressed by using baculoviral vectors in insect cells and incorporated into a monoclonal antibody-enhanced immunofluorescence assay (mIFA) termed the Sf9 three-antigen mIFA. The results obtained by this mIFA were compared to those obtained by a standard mIFA with an HHV-8-infected B-cell line (BC3 mIFA). Test sera were obtained from patients diagnosed with KS, human immunodeficiency virus type 1-infected patients at high risk for HHV-8 infection, and healthy controls from a local blood bank. The combined use of both assays had a sensitivity of 94% and a specificity of 96%. The performance of these two assays when they were used together indicates that they may be useful for the reliable detection of HHV-8-specific immunoglobulin G antibodies in a population.

Estimation of human herpesvirus 8 prevalence in high-risk patients by analysis of humoral and cellular immunity

BACKGROUND

Immunocompromized individuals, such as patients with end-stage renal disease, transplant recipients, and HIV-infected patients, are at increased risk of acquiring human herpesvirus (HHV)-8 associated infectious complications. The prevalence of HHV-8 infection generally is determined by detection of immunoglobulin G. However, because serological assays differ greatly, estimations on the actual HHV-8 prevalence vary considerably.

METHODS

HHV-8-specific cellular and humoral immunity were analyzed in 128 controls, 73 patients on dialysis, 67 transplant recipients, and 69 HIV-infected patients with the use of flow cytometry and indirect immunofluorescence microscopy.

RESULTS

A higher seroprevalence (from 13.7% to 44.9%) was confirmed for all groups of immunocompromised individuals as compared with healthy controls (3.9%). Among immunocompetent individuals, as little as 12.5% had HHV-8 reactive T-cell frequencies greater than the detection limit. In line with a higher seroprevalence in immunosuppressed patients, HHV-8-specific T cells were detectable in 30.1% of dialysis patients, 20.9% of transplant recipients, and 24.6% of HIV-infected individuals. When combining the individual presence of either HHV-8-specific antibodies or T cells or both, the prevalence of HHV-8 infection approached 15.6% in healthy individuals and 41.1%, 40.3%, and 55.1% in dialysis patients, transplant recipients, and HIV-infected individuals, respectively.

CONCLUSIONS

The exclusive serological analysis considerably underestimates the prevalence of HHV-8 infection in all study groups. Thus, the combined quantitation of both humoral and cellular immunity may instead be a superior method to assign the individual HHV-8 status. Moreover, this study suggests that the relative contributions of humoral and cellular immunity in control of HHV-8 may be different depending on the type of immunodeficiency.

Human herpesvirus 8--a novel human pathogen

In 1994, Chang and Moore reported on the latest of the gammaherpesviruses to infect humans, human herpesvirus 8 (HHV-8) [1]. This novel herpesvirus has and continues to present challenges to define its scope of involvement in human disease. In this review, aspects of HHV-8 infection are discussed, such as, the human immune response, viral pathogenesis and transmission, viral disease entities, and the virus's epidemiology with an emphasis on HHV-8 diagnostics.

Human Herpesvirus 8 DNA in Serum During Seroconversion in Allogeneic Bone Marrow Transplant Recipients

To determine the prevalence of human herpesvirus 8 (HHV-8) infection, the rate of HHV-8 seroconversion, and the presence of serum HHV-8 DNA after bone marrow transplantation (BMT), we evaluated sera from 187 Italian BMT donor-recipient pairs. Antibodies to lytic and latent HHV-8 antigens were detected by immunofluorescence. Sera of donor-recipient pairs who seroconverted were examined by real-time polymerase chain reaction (RT-PCR). Before BMT, 24 (13%) of 187 donors and 20 (11%) of 187 recipients were seropositive; after BMT, 28 (15%) of 187 recipients were seropositive. Seroconversion occurred in 19 (11%) of 167 recipients seronegative at baseline: 14 (9%) from 149 seronegative donors and five (28%) from 18 seropositive donors (relative risk of seroconversion with BMT from a seropositive donor = 2.96, 95% confidence interval = 1.21 to 7.25; P = .02, two-sided Fisher's exact test). One donor and two recipients who seroconverted after BMT were positive for HHV-8 by RT-PCR. No HHV-8-related complications were observed after a median follow-up of 6 years. BMT-associated HHV-8 seroconversion is relatively common in seronegative recipients from seropositive donor, but factors other than BMT may also contribute to seroconversion.