Detection of human herpesvirus 8 by quantitative polymerase chain reaction: development and standardisation of methods

Human Herpesvirus 8 in Australia: DNAemia and Cumulative Exposure in Blood Donors

Human herpesvirus 8 (HHV-8), the causative agent of Kaposi’s sarcoma, multicentric Castleman’s disease and primary effusion lymphoma, predominantly manifests in immunocompromised individuals. However, infection in immunocompetent individuals does occur. The prevalence of HHV-8 exposure in blood donors from non-endemic countries ranges between 1.2% and 7.3%. Nothing was known about the prevalence in Australian blood donors. Therefore, this study investigated the active and cumulative exposure of HHV-8 in this cohort. Plasma samples (n = 480) were collected from eastern Australian blood donors and were tested for HHV-8 DNA by qPCR, and for HHV-8 antibodies by two different ELISAs. Samples initially positive on either ELISA were retested in duplicate on both, and on a mock-coated ELISA. Any samples positive two or three out of the three times tested on at least one ELISA, and repeat negative on the mock-coated ELISA, were assigned as repeat positive. None of the 480 samples tested contained HHV-8 DNA. Serological testing revealed 28 samples (5.83%; 95% CI: 3.74−7.93%) had antibodies to HHV-8. There was no difference (p > 0.05) in seropositivity between sex or with increasing age. This is the first study to show serological evidence of cumulative HHV-8 exposure and no HHV-8 DNAemia within a select blood donor population in Australia. Our molecular and serological data is consistent with published results for blood donors residing in HHV-8 non-endemic countries, which shows the prevalence to be very low.

Common oral opportunistic infections in Human Immunodeficiency Virus infection/Acquired Immunodeficiency Syndrome: Changing epidemiology; diagnostic criteria and methods; management protocols

There were 36.9 million in the world living with human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS) as of 2017, and new infections have seen a reduction by 18% since 2010. But this rate of decline is not sufficient for the goal of eradication of AIDS by 2030. Only 21.7  million people infected with HIV have accesses to antiretroviral therapy, with the rest at risk of the potential complications of HIV infection. It has been shown that oral lesions are diagnostic and prognostic of HIV infection, and many oral opportunistic infections continue to be a major problem, particularly in developing countries. It is therefore important that dental surgeons be aware and updated to recognize and manage the oral effects of HIV infection/AIDS. This chapter describes the classification, diagnosis, and management of oral lesions in these patients, based on our current understanding of the infection. This review also discusses the standardization of diagnosis of oral lesions in HIV infection/AIDS patients, immune reconstitution inflammatory syndrome case definition, and the research priorities formulated at the 7th World Workshop on Oral Health and Disease in AIDS.

The Kaposi's Sarcoma-Associated Herpesvirus Protein ORF42 Is Required for Efficient Virion Production and Expression of Viral Proteins

Kaposi’s sarcoma-associated herpesvirus (KSHV), the etiologic agent of Kaposi’s sarcoma and other aggressive AIDS-associated malignancies, encodes over 90 genes, most of which are expressed only during the lytic replication cycle. The role of many of the KSHV lytic proteins in the KSHV replication cycle remains unknown, and many proteins are annotated based on known functions of homologs in other herpesviruses. Here we investigate the role of the previously uncharacterized KSHV lytic protein ORF42, a presumed tegument protein. We find that ORF42 is dispensable for reactivation from latency but is required for efficient production of viral particles. Like its alpha- and beta-herpesviral homologs, ORF42 is a late protein that accumulates in the viral particles. However, unlike its homologs, ORF42 appears to be required for efficient expression of at least some viral proteins and may potentiate post-transcriptional stages of gene expression. These results demonstrate that ORF42 has an important role in KSHV replication and may contribute to shaping viral gene expression.

Transcriptome profiling of the rumen epithelium of beef cattle differing in residual feed intake

Background

Feed efficient cattle consume less feed and produce less environmental waste than inefficient cattle. Many factors are known to contribute to differences in feed efficiency, however the underlying molecular mechanisms are largely unknown. Our study aimed to understand how host gene expression in the rumen epithelium contributes to differences in residual feed intake (RFI), a measure of feed efficiency, using a transcriptome profiling based approach.

Results

The rumen epithelial transcriptome from highly efficient (low (L-) RFI, n = 9) and inefficient (high (H-) RFI, n = 9) Hereford x Angus steers was obtained using RNA-sequencing. There were 122 genes differentially expressed between the rumen epithelial tissues of L- and H- RFI steers (p < 0.05) with 85 up-regulated and 37 down-regulated in L-RFI steers. Functional analysis of up-regulated genes revealed their involvement in acetylation, remodeling of adherens junctions, cytoskeletal dynamics, cell migration, and cell turnover. Additionally, a weighted gene co-expression network analysis (WGCNA) identified a significant gene module containing 764 genes that was negatively correlated with RFI (r = −0.5, p = 0.03). Functional analysis revealed significant enrichment of genes involved in modulation of intercellular adhesion through adherens junctions, protein and cell turnover, and cytoskeletal organization that suggest possible increased tissue morphogenesis in the L-RFI steers. Additionally, the L-RFI epithelium had increased expression of genes involved with the mitochondrion, acetylation, and energy generating pathways such as glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation. Further qPCR analysis of steers with different RFI (L-RFI, n = 35; M-RFI, n = 34; H-RFI, n = 35) revealed that the relative mitochondrial genome copy number per cell of the epithelium was positively correlated with RFI (r = 0.21, p = 0.03).

Conclusions

Our results suggest that the rumen epithelium of L-RFI (efficient) steers may have increased tissue morphogenesis that possibly increases paracellular permeability for the absorption of nutrients and increased energy production to support the energetic demands of increased tissue morphogenesis compared to those of H-RFI (inefficient) animals. Greater expression of mitochondrial genes and lower relative mitochondrial genome copy numbers suggest a greater rate of transcription in the rumen epithelial mitochondria of L-RFI steers. Understanding how host gene expression profiles are associated with RFI could potentially lead to identification of mechanisms behind this trait, which are vital to develop strategies for the improvement of cattle feed efficiency.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2935-4) contains supplementary material, which is available to authorized users.

Comorbidities associated with HIV and antiretroviral therapy (clinical sciences): a workshop report

In the era of combination antiretroviral therapy (ART), parsing out the effects of HIV vs ART on health outcomes is challenging. Nadir CD4 count, a marker of the extent of immunosuppression, has significant long-term impact on an array of disease states in HIV+ persons; however, in the dental literature, reporting of pre-ART exposure to immunosuppression has largely been ignored and this limits the validity of previous studies. In Workshop A1, we explain fully the importance of nadir CD4, pre-ART immunosuppression, and identify a need to include specific variables in future research. The questions posed herein are challenging, typically not neatly addressed by any one study and require integration of the latest evidence from the wider medical literature. We consider topics beyond the confines of the oral cavity and examine oral health in the complex context of ART era HIV immunopathophysiology. We depict how variability in geographic setting and time period (pre- and post-ART era) can impact oral conditions - influencing when HIV infection was detected (at what CD4 count), the type and timing of ART as well as social determinants such as strong stigma and limited access to care. We hope our Workshop will stir debate and energize a rigorous focus on relevant areas of future research in HIV/AIDS.

Diagnostic challenges of oral and cutaneous Kaposi's sarcoma in resource-constrained settings

OBJECTIVES

Kaposi's sarcoma (KS), caused by HHV-8, is the most frequent HIV-associated malignancy worldwide and remains a major scourge in Sub-Saharan Africa. KS is also endemic in much of Africa. There is a risk of misdiagnosis based solely on clinical appearance and haematoxylin and eosin (H&E) staining, especially with other reactive and neoplastic vascular proliferations which occur in the mouth. This study examined oral and cutaneous biopsies from clinically diagnosed lesions of KS in Kenya, using histopathology supplemented with immunohistochemistry (IHC) and polymerase chain reaction (PCR) for HHV-8 as confirmation of diagnosis.

METHODS

Biopsies of 49 lesions (28 oral, 21 cutaneous) previously diagnosed as 'KS' were re-examined by H&E staining and IHC targeting HHV-8 LANA-1. Positive controls were sections from embedded BCBL-1 cell lines. Negative controls were from three different HHV-8-negative biopsies. Confirmation of HHV-8 immunohistochemistry was sought by PCR and by determining the HHV-8 ORFK1 subtype.

RESULTS

Whilst most cases were confirmed, 12 oral and 4 cutaneous lesions displayed clinical and histological features of KS but were negative to HHV-8 IHC. These oral lesions were re-diagnosed as pyogenic granulomata (n = 6), deep mycosis (n = 1), inflamed mucosa (n = 2) or 'uncertain but not KS' (n = 3). Whilst PCR is usually helpful in differentiating HHV-8 disease, all samples were HHV-8 PCR positive, with identical sequences, suggesting cross-contamination of samples in the original pathology laboratories.

CONCLUSION

HHV-8 IHC is essential for the correct diagnosis of KS, but due to the high level of contamination in resource-poor settings, PCR is inadvisable.

Detecting DNA viruses in oral fluids: evaluation of collection and storage methods

Storing saliva for nucleic acid diagnostics is problematic in resource-constrained settings. DNA Genotek's OMNIgene™·DISCOVER kit aims to stabilise microbial DNA at room temperature. We evaluate this for long-term storage, determining DNA quantity/purity and human herpesvirus 8 (HHV-8) load as indicator. Viral loads and DNA degradation were assayed over 14months in HHV-8-negative saliva spiked with cell-associated and cell-free virus and saliva collected fresh frozen and into kits from 10 HIV-positive patients. Viral loads remained constant for 6-9months, yielding high quantities of DNA: subsequent losses were ≤48%. Patient samples, frozen or kit stored, produced pure DNA of comparable concentration. Higher HHV-8 detection in frozen saliva resulted from losses during ethanol precipitation using kits. After 14months, DNA degradation was significant in frozen saliva, but that in kits had integrity similar to fresh samples. Storing frozen saliva is detrimental. This kit is well suited for collection, long-term storage, and assay of viral DNA in resource-constrained settings.

Successful treatment of iatrogenic multicentric Castleman's disease arising due to recrudescence of HHV-8 in a liver transplant patient

We describe the case of a 59-year-old HIV-negative male who developed multicentric Castleman's disease (MCD) 1 year postliver transplantation due to recrudescence of a pretransplant human herpesvirus-8 (HHV-8) infection. He presented with fevers, dry cough, weight loss and drenching night sweats. Routine investigations were all unremarkable. Computerized axial tomography (CT) scans showed splenomegaly and intra-abdominal lymphadenopathy, confirmed by positron emission tomography. Cervical lymph node biopsies were consistent with MCD. The presence of HHV-8 was confirmed on immunohistochemistry. Peripheral blood HHV-8 quantitative polymerase chain reaction (qPCR) monitoring showed a threefold decrease in viremia in the first week of treatment with ganciclovir but had little impact on clinical symptoms. Reducing immunosuppression and switching to rituximab resolved clinical symptoms and produced a negative HHV-8 qPCR result. Retrospective molecular testing of sera collected pre- and immediately posttransplantation confirmed preexisting HHV-8 in the host. This is the first reported case of an HIV-negative postliver transplant patient developing MCD that manifested as posttransplant lymphoproliferative disorder due to recrudescence of HHV-8. We propose (1) the introduction of the term iatrogenic Castleman's disease (CD) for this and similar cases, (2) rituximab should be considered as a treatment option for CD and (3) consideration be given to a change to the World Health Organization classification of CD to incorporate such cases.

Comparison of salivary collection and processing methods for quantitative HHV-8 detection

OBJECTIVES

Saliva is a proved diagnostic fluid for the qualitative detection of infectious agents, but the accuracy of viral load determinations is unknown. Stabilising fluids impede nucleic acid degradation, compared with collection onto ice and then freezing, and we have shown that the DNA Genotek P-021 prototype kit (P-021) can produce high-quality DNA after 14 months of storage at room temperature. Here we evaluate the quantitative capability of 10 collection/processing methods.

METHODS

Unstimulated whole mouth fluid was spiked with a mixture of HHV-8 cloned constructs, 10-fold serial dilutions were produced, and samples were extracted and then examined with quantitative PCR (qPCR). Calibration curves were compared by linear regression and qPCR dynamics.

RESULTS

All methods extracted with commercial spin columns produced linear calibration curves with large dynamic range and gave accurate viral loads. Ethanol precipitation of the P-021 does not produce a linear standard curve, and virus is lost in the cell pellet. DNA extractions from the P-021 using commercial spin columns produced linear standard curves with wide dynamic range and excellent limit of detection.

CONCLUSION

When extracted with spin columns, the P-021 enables accurate viral loads down to 23 copies μl(-1) DNA. The quantitative and long-term storage capability of this system makes it ideal for study of salivary DNA viruses in resource-poor settings.

Successful treatment of an HIV-positive patient with unmasking Kaposi's sarcoma immune reconstitution inflammatory syndrome

BACKGROUND

Kaposi's sarcoma (KS) continues to be the most common human immunodeficiency virus (HIV)-associated neoplasm with considerable morbidity and mortality. While lesions normally resolve upon initiation of antiretroviral therapy (ART), recrudescence or unmasking of KS lesions may occur as part of immune reconstitution inflammatory syndrome (IRIS). Treatment of unmasking KS-IRIS is not yet standardised.

OBJECTIVES

To report the successful treatment of a patient with fulminating mucocutaneous unmasking KS-IRIS by maintaining ART and using pegylated liposomal doxorubicin (PLD).

STUDY DESIGN

The patient, a 39-year-old HIV-positive male with no previous history of KS presented with a 2-week history of cutaneous and oral KS lesions that had disseminated rapidly over the preceding 4 days. The KS lesions appeared 8 weeks after recommencing ART. At the time of this presentation, his CD4+ count was 742 cells/mm(3) with a HIV viral load <400 copies/ml. ART was maintained and treatment with PLD commenced.

RESULTS

Despite the rapid dissemination of KS lesions, virus was undetectable in plasma. In a late-stage vasoformative lesion, immunohistochemistry (IHC) for human herpesvirus 8 (HHV-8) antigen was light and diffuse, with stippled deposits within endothelial cell nuclei. Virus extracted from the lesion was HHV-8 subtype A. The patient responded well to PLD, relapsed a year later, but after further PLD, has remained well for the following 5 years.

CONCLUSION

Despite the absence of HHV-8 viraemia, this is clearly a case of unmasking KS-IRIS. It demonstrates that this entity can be successfully treated by maintaining ART and administering PLD.