Identification of novel gene signatures in patients with atopic dermatitis complicated by eczema herpeticum

Abstract

Background: A subset of patients with atopic dermatitis (AD) is prone to disseminated herpes simplex virus (HSV) infection (ie, atopic dermatitis with a history of eczema herpeticum [ADEH+]). Biomarkers that identify ADEH+ are lacking.

Objective: We sought to search for novel ADEH+ gene signatures in PBMCs.

Methods: An RNA-sequencing approach was applied to evaluate global transcriptional changes by using PBMCs from patients with ADEH+ and patients with atopic dermatitis without a history of eczema herpeticum (ADEH-). Candidate genes were confirmed by means of quantitative PCR or ELISA.

Results: PBMCs from patients with ADEH+ had distinct changes to the transcriptome when compared with those from patients with ADEH- after HSV-1 stimulation: 792 genes were differentially expressed at a false discovery rate of less than 0.05 (ANOVA), and 15 type I and type III interferon genes were among the top 20 most downregulated genes in patients with ADEH+. We further validated that IFN-α and IL-29 mRNA and protein levels were significantly decreased in HSV-1-stimulated PBMCs from patients with ADEH+ compared with those from patients with ADEH- and healthy subjects. Ingenuity Pathway Analysis demonstrated that the upstream regulators of type I and type III interferons, interferon regulatory factor (IRF) 3 and IRF7, were significantly inhibited in patients with ADEH+ based on the downregulation of their target genes. Furthermore, we found that gene expression of IRF3 and IRF7 was significantly decreased in HSV-1-stimulated PBMCs from patients with ADEH+.

Conclusions: PBMCs from patients with ADEH+ have a distinct immune response after HSV-1 exposure compared with those from patients with ADEH-. Inhibition of the IRF3 and IRF7 innate immune pathways in patients with ADEH+ might be an important mechanism for increased susceptibility to disseminated viral infection.

Keywords: Atopic dermatitis; eczema herpeticum; herpes simplex virus; interferon regulatory factor 3; interferon regulatory factor 7; type I interferon; type III interferon.

Conflict of interest statement

The authors have no financial conflict of interest related to this manuscript.

Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. ADEH+ PBMCs expression profiles are distinct from ADEH− after HSV-1 exposure

A) Venn diagram of genes significantly different (FDR

Figure 2. The induction of IFN-α by HSV-1 is significantly decreased in ADEH+

A) IFNA4 and B) IFNA5 mRNA levels were evaluated by real-time qPCR in sham and HSV-1 treated PBMCs from normal (n=20), ADEH− (n=20) and ADEH+ (n=20). C) IFN-α protein levels were evaluated by ELISA in the culture supernatants from HSV-1 stimulated PBMCs from normal subjects (n=20), ADEH− (n=20) and ADEH+ (n=20).

Figure 3. The induction of type III IFN IL-29 by HSV-1 is significantly decreased in ADEH+

A) IL-29 mRNA level was evaluated by real-time qPCR in sham and HSV-1 treated PBMCs from normal (n=20), ADEH− (n=20) and ADEH+ (n=20); B) IL-29 protein levels in HSV-1 stimulated PBMCs from normal (n=20), ADEH− (n=20) and ADEH+ (n=20) were evaluated by ELISA.

Figure 4. Up-stream regulators of type I and type III IFNs were inhibited in ADEH+

A) IPA analysis demonstrated that 5 IRFs are predicted to be inhibited in ADEH+. Each IRF is connected with its target genes; dashed and solid connecting lines indicate an indirect or direct relationship with the master regulator respectively. The colors of lines connecting IRFs and their corresponding targets indicate the predicted activation status of the IRF gene based on expression patterns of its target genes. B) Statistical parameters of 5 IRFs.

Figure 5

IRF3 and IRF7 are significantly decreased in HSV-1 stimulated ADEH+ PBMCs. IRF3 (A) and IRF7 (B) mRNA levels were evaluated by real-time qPCR.