RNA sequencing of the i human herpesvirus 6B transcriptome to identify targets for clinical assays distinguishing between latent and active infections.

Publication Type:

Journal Article

Source:

Journal of virology (2018)

Keywords:

Bioinformatics Core Facility; Genomics Core Facility

Abstract:

Human herpesvirus 6B (HHV-6B) DNA is frequently detected in human samples. Diagnostic assays distinguishing HHV-6B reactivation from latency are limited. This has impaired strategies to diagnose and treat HHV-6B-associated diseases. We used RNA sequencing to characterize and compare the HHV-6B transcriptome in multiple sample types, including 1) whole blood from hematopoietic cell transplant (HCT) recipients with and without HHV-6B plasma viremia; 2) tumor tissue samples from subjects with large B cell lymphoma infected with HHV-6B; 3) lymphoblastoid cell lines (LCLs) from subjects with inherited chromosomally integrated HHV-6B or latent infection with HHV-6B; and 4) HHV-6B Z29 infected SupT1 CD4+ T cells. We demonstrated substantial overlap in the HHV-6B transcriptome observed in and samples, although there was variability in the breadth and quantity of gene expression across samples. The HHV-6B viral polymerase gene U38 was the only HHV-6B transcript detected in all RNA-seq data sets and was one of the most highly expressed genes. We developed a novel reverse transcription PCR assay targeting HHV-6B U38, which identified U38 messenger RNA in all tested whole blood samples from patients with concurrent HHV-6B viremia. No HHV-6B U38 transcripts were detected by RNA-seq or RT-qPCR in whole blood samples from subjects without HHV-6B plasma detection or from latently infected LCLs. A RT-qPCR assay for HHV-6B U38 may be useful to identify lytic HHV-6B infection in non-plasma samples and samples from individuals with inherited chromosomally integrated HHV-6B. This study also demonstrates the feasibility of transcriptomic analyses in HCT recipients. Human herpesvirus 6B (HHV-6B) is a DNA virus that infects most children within the first few years of life. After primary infection, HHV-6B persists as a chronic, latent infection in many cell types. Additionally, HHV-6B can integrate into germline chromosomes, resulting in individuals with viral DNA in every nucleated cell. Given that PCR to detect viral DNA is the mainstay for diagnosing HHV-6B infection, the characteristics of HHV-6B infection complicate efforts to distinguish between latent and active viral infection, particularly in immunocompromised patients who have frequent HHV-6B reactivation. In this study, we used RNA sequencing to characterize the HHV-6B gene expression profile in multiple sample types, and our findings identified evidence-based targets for diagnostic tests that distinguish between latent and active viral infection.