Editor's Comment: This interesting study examines the link between allergies and herpesvirus reactivation.The author of the article proposes that individuals with allergies (atopic individuals) may be prone to more severe and atypical herpes-related illnesses, due to a TH2 shift in their immune systems. Interestingly, the reactivation of latent herpesviruses can actually provoke this shift by increasing the expression of immune-suppressing cytokines, such as IL-10 and IL-6. The author recommends treatment with antivirals for atopic patients who present with atypical symptoms of herpesvirus reactivation. The reactivation of latent herpesvirus due to a TH2 shift has long been proposed as one of the pathological mechanisms of CFS/ME. This study provides further support for the role of antivirals as a treatment for a subset of CFS/ME patients, particularly those with a history of allergies.
Herpes viruses and the microbiome
By David H. Dreyfus
The focus of this article will be to examine the role of common herpesviruses as a component of the microbiome of atopic patients and to review clinical observations suggesting that atopic patients might be predisposed to more severe and atypical herpes-related illness because their immune response is biased toward a TH2 cytokine profile. Human populations are infected with 8 herpesviruses, including herpes simplex virus HSV1 and HSV2 (also termed HHV1 and HHV2), varicella zoster virus (VZV or HHV3), EBV (HHV4), cytomegalovirus (HHV5), HHV6, HHV7, and Kaposi sarcoma–associated herpesvirus (termed KSV or HHV8). Herpesviruses are highly adapted to lifelong infection of their human hosts and thus can be considered a component of the human “microbiome” in addition to their role in illness triggered by primary infection. HSV1 and HSV2 infection and reactivation can present with more severe cutaneous symptoms termed eczema herpeticum in the atopic population, similar to the more severe eczema vaccinatum, and drug reaction with eosinophilia and systemic symptoms syndrome (DRESS) is associated with reactivation of HSV6 and possibly other herpesviruses in both atopic and nonatopic patients. In this review evidence is reviewed that primary infection with herpesviruses may have an atypical presentation in the atopic patient and conversely that childhood infection might alter the atopic phenotype. Reactivation of latent herpesviruses can directly alter host cytokine profiles through viral expression of cytokine-like proteins, such as IL-10 (EBV) or IL-6 (cytomegalovirus and HHV8), viral encoded and secreted siRNA and microRNAs, and modulation of expression of host transcription pathways, such as nuclear factor ?B. Physicians caring for allergic and atopic populations should be aware of common and uncommon presentations of herpes-related disease in atopic patients to provide accurate diagnosis and avoid unnecessary laboratory testing or incorrect diagnosis of other conditions, such as drug allergy or autoimmune disease. Antiviral therapy and vaccines should be administered promptly when indicated clinically.
Source: The Journal of Allergy and Clinical Immunology, 22 April 2013 (10.1016/j.jaci.2013.02.039). David H. Dreyfus. Department of Pediatrics, Clinical Faculty, Yale School of Medicine, New Haven and the Center for Allergy, Asthma, and Immunology, Waterbury, Conn