Calibration technologies for correct determination of Epstein-Barr Virus, human herpesvirus 6 (HHV-6), and HHV-8 antiviral drug susceptibilities by use of real-time-PCR-based assays

Modulation of gene expression in Kaposi’s sarcoma-associated herpesvirus-infected lymphoid and epithelial cells

Aim: To evaluate the gene expression changes that occur soon after the active infection of two susceptible cell types with human herpesvirus 8 (HHV-8). Materials & methods: The expression profile of 282 human genes involved in the inflammatory process was investigated in HHV-8 A1 or C3 subtype-infected and mock-infected human epithelial cells and lymphoid cells. Results: The HHV-8-induced transcriptional profiles in the epithelial and lymphoid cells were very different. A robust increase in the expression was found in genes belonging to different categories, especially the categories of inflammation response and signal transduction. Conclusion: These results indicate that during early infection, HHV-8 induces a variety of cell type-specific processes, thus providing infection signatures useful as potential targets for therapeutic intervention.

HHV-8 DNA replication correlates with the clinical status in AIDS-related Kaposi's sarcoma

BACKGROUND

The value of plasma levels of human herpesvirus 8 (HHV-8) DNA as a marker of clinical status in acquired immunodeficiency syndrome-related Kaposi's sarcoma (AIDS-KS) remains to be elucidated.

OBJECTIVES

To investigate the relationship between the plasma HHV-8 DNA viral load and the clinical status of AIDS-KS.

STUDY DESIGN

A total of 378 blood samples were obtained from 62 patients with AIDS-KS followed longitudinally. All patients received antiretroviral therapy (ART) or anti-neoplastic therapy. The patients were divided into four groups according to their clinical status: onset disease (OD), progressive disease (PD), stable or partial remission (S/PR) and complete remission (CR).

RESULTS

Plasma HHV-8 DNAaemia was detected in all samples obtained from patients with OD or PD (100%); in contrast, HHV-8 DNAaemia was found only in a minority of patients with CR (8%) and was invariably undetectable in patients with stable CR. HHV-8 DNA detection in plasma was strongly associated with an unfavourable outcome (odds ratio=231.9; p<0.0001). Conversely, neither the HIV-1 viral load nor peripheral CD4(+) T-cell counts were associated with the KS clinical status, though both parameters did affect HHV-8 DNAaemia levels (p<0.0001). Multivariate analysis confirmed that HHV-8 DNAaemia was strongly and independently correlated with both clinical status (p<0.05) and HIV-1 plasma viraemia (p=0.027).

CONCLUSIONS

The strong association of plasma HHV-8 DNAaemia with onset or progressive disease is compatible with an active role of replicating virus in clinically active AIDS-KS. An accurate evaluation of the plasma HHV-8 load might be useful for monitoring AIDS-KS under antiretroviral or antineoplastic therapy.

Absolute quantification of viral DNA: the quest for perfection

In spite of the impressive technical refinement of the PCR technology, new-generation real-time PCR assays still suffer from two major limitations: the impossibility to control both for PCR artifacts (with the important caveat of false-negative results) and for the efficiency of nucleic acid recovery during the preliminary extraction phase of DNA from the biological sample. The calibrator technology developed at the Unit of Human Virology overcomes both of these limitations, leading to a substantially higher degree of accuracy and reproducibility in the quantification, which is especially useful for the measurement of pathogen loads in sequential samples and for the reliable detection of low-copy pathogens.