Association of varicella zoster virus with giant cell arteritis

Varicella Zoster Virus in Giant Cell Arteritis: A Review of Current Medical Literature

In recent years, the search for the cause of giant cell arteritis (GCA) has led investigators to look to varicella zoster virus (VZV) as the answer. In some ways, the nature of VZV infection makes it an attractive explanation for the pathology observed in GCA. However, studies to date yield a level of inconsistency that still leaves uncertainty as to whether VZV directly causes GCA, and positive findings have not been successfully reproduced.

Risk of Stroke/Transient Ischemic Attack or Myocardial Infarction with Herpes Zoster: A Systematic Review and Meta-Analysis

BACKGROUND

Accumulating evidence indicates that herpes zoster (HZ) may increase the risk of stroke/transient ischemic attack (TIA) or myocardial infarction (MI), but the results are inconsistent. We aim to explore the relationship between HZ and risk of stroke/TIA or MI and between herpes zoster ophthalmicus (HZO) and stroke.

METHODS

We estimated the relative risk (RR) and 95% confidence intervals (CIs) with the meta-analysis. Cochran's Q test and Higgins I² statistic were used to check for heterogeneity.

RESULTS

HZ infection was significantly associated with increased risk of stroke/TIA (RR = 1.30, 95% CI: 1.17-1.46) or MI (RR = 1.18, 95% CI: 1.07-1.30). The risk of stroke after HZO was 1.91 (95% CI 1.32-2.76), higher than that after HZ. Subgroup analyses revealed increased risk of ischemic stroke after HZ infection but not hemorrhagic stroke. The risk of stroke was increased more at 1 month after HZ infection than at 1-3 months, with a gradual reduced risk with time. The risk of stroke after HZ infection was greater with age less than 40 years than 40-59 years and more than 60 years. Risk of stroke with HZ infection was greater without treatment than with treatment and was greater in Asia than Europe and America but did not differ by sex.

CONCLUSIONS

Our study indicated that HZ infection was associated with increased risk of stroke/TIA or MI, and HZO infection was the most marked risk factor for stroke. Further studies are needed to explore whether zoster vaccination could reduce the risk of stoke/TIA or MI.

Blinded search for varicella zoster virus in giant cell arteritis (GCA)-positive and GCA-negative temporal arteries

Recent analysis of archived temporal arteries (TAs) acquired from 13 pathology laboratories in the US, Canada, Iceland, France, Germany and Israel from patients with pathologically-verified giant cell arteritis (GCA-positive) and TAs from patients with clinical features and laboratory abnormalities of GCA but whose TAs were pathologically negative (GCA-negative) revealed VZV antigen in most TAs from both groups. Despite formalin-fixation, VZV DNA was also found in many VZV-antigen positive sections that were scraped, subjected to DNA extraction, and examined by PCR with VZV-specific primers. Importantly, in past studies, the pathological diagnosis (GCA-positive or -negative) was known to the neurovirology laboratory. Herein, GCA-positive and GCA-negative TAs were provided by an outside institution and examined by 4 investigators blinded to the pathological diagnoses. VZV antigen was found in 3/3 GCA-positive TAs and in 4/6 GCA-negative TAs, and VZV DNA in 1/3 VZV antigen-positive, GCA-positive TAs and in 3/4 VZV antigen-positive, GCA-negative TAs. VZV DNA was also detected in one GCA-negative, VZV-antigen negative TA. Overall, the detection of VZV antigen in 78% of GCA-positive and GCA-negative TAs is consistent with previous reports on the prevalence of VZV antigen in patients with clinically suspect GCA.

Risk of Stroke and Myocardial Infarction After Herpes Zoster in Older Adults in a US Community Population

OBJECTIVE

To assess the risk of stroke and myocardial infarction (MI) after herpes zoster in a US community population of older adults.

PATIENTS AND METHODS

We performed a community cohort study (January 1, 1986, to October 1, 2011) comparing the risk of stroke and MI in 4862 adult residents of Olmsted County, Minnesota, 50 years and older with and without herpes zoster and 19,433 sex- and age-matched individuals with no history of herpes zoster. Odds ratios are presented for MI and stroke at 3, 6, 12, and 36 months after index herpes zoster plus hazard ratios for long-term risk (up to 28.6 years).

RESULTS

Individuals with herpes zoster had more risk or confounding factors for MI and stroke, suggesting that they had worse health status overall. When controlling for the multiple risk factors, those with herpes zoster were at increased risk for stroke at 3 months after herpes zoster compared with those without a history of herpes zoster (odds ratio, 1.53; 95% CI, 1.10-2.33; P=.04). The association between herpes zoster and MI at 3 months was not robust across analytic methods. Herpes zoster was not associated with an increased risk of stroke or MI at any point beyond 3 months.

CONCLUSIONS

Herpes zoster was associated with only a short-term increased risk of stroke, which may be preventable with the prevention of herpes zoster.

Pathogenesis of varicelloviruses in primates

Varicelloviruses in primates comprise the prototypic human varicella-zoster virus (VZV) and its non-human primate homologue, simian varicella virus (SVV). Both viruses cause varicella as a primary infection, establish latency in ganglionic neurons and reactivate later in life to cause herpes zoster in their respective hosts. VZV is endemic worldwide and, although varicella is usually a benign disease in childhood, VZV reactivation is a significant cause of neurological disease in the elderly and in immunocompromised individuals. The pathogenesis of VZV infection remains ill-defined, mostly due to the species restriction of VZV that impedes studies in experimental animal models. SVV infection of non-human primates parallels virological, clinical, pathological and immunological features of human VZV infection, thereby providing an excellent model to study the pathogenesis of varicella and herpes zoster in its natural host. In this review, we discuss recent studies that provided novel insight in both the virus and host factors involved in the three elementary stages of Varicellovirus infection in primates: primary infection, latency and reactivation.