Varicella-zoster virus-specific enzyme-linked immunospot assay responses and zoster-associated pain in herpes zoster subjects.

Varicella-Zoster Virus-Specific Enzyme-Linked Immunospot Assay Responses and Zoster-Associated Pain in Herpes Zoster Subjects Stephen K. Tyring,a Jon E. Stek,b Jeffrey G. Smith,b Jin Xu,b Marco Pagnoni,b Ivan S. F. Chan,b Jeffrey L. Silber,b Janie Parrino,b and Myron J. Levinc University of Texas Health Sciences Center, Houston, Texas, USAa; Merck Sharp & Dohme Corp., Whitehouse Station, New Jersey, USAb; and University of Colorado Denver and Health Sciences Center, Aurora, Colorado, USAc Varicella-zoster virus (VZV)-specific cell-mediated immunity (CMI) responses were compared over time following an episode of herpes zoster (HZ) with those of age-, race-, and gender-matched healthy controls (HC) without HZ, using a validated gamma interferon (IFN-␥) enzyme-linked immunospot (ELISPOT) assay. The zoster brief-pain inventory (ZBPI) was used to assess zoster-associated pain. HZ patients (n ⴝ 140) had significantly higher IFN-␥ ELISPOT responses to VZV antigen than did HC (n ⴝ 140). ELISPOT geometric mean count (GMC) responses (with 95% confidence intervals [CI]) for subjects who presented within 72 h were as follows: for HZ patients > 60 years of age, at day 0 the GMC was 110 and at week 2 the GMC was 235; for HZ patients 21 to 59 years of age, at day 0 the GMC was 111 and at week 2 the GMC was 198; for HC > 60 years of age, at day 0 the GMC was 19 and at week 2 the GMC was 18; and for HC 21 to 59 years of age, at day 0 the GMC was 59 and at week 2 the GMC was 56. The mean pain score (95% CI) across age groups at 1 week postrash (n ⴝ 106) was 6.0 (5.5, 6.5) and at 2 weeks postrash (n ⴝ 119) was 3.5 (2.9, 4.0). The percentage of HZ patients with substantial pain (score > 3) at 6 weeks postrash increased with age from 8% for patients 21 to 49 years of age to 16% for patients 50 to 59 years of age to 22% for patients > 60 years of age. The VZV-specific CMI response was substantially boosted by an episode of HZ, as measured by ELISPOT results. Older adults had lower VZVspecific cellular immunity than younger subjects at baseline, but the boosting effect of HZ was substantial for all age groups. HZ patients experienced considerable zoster-associated acute (1 to 2 weeks after rash) pain across age groups, while chronic pain increased with age. V aricella-zoster virus (VZV) develops a permanent latent association with neurons in spinal and cranial sensory nerve ganglia during primary infection (varicella) (9, 20). Herpes zoster (HZ; shingles), which is the result of reactivation of this latent VZV infection, is characterized by a painful, unilateral, dermatomal, vesicular rash (5, 7, 14). There is a close correlation between the age-related incidence of HZ and the age-related decline in VZV-specific cell-mediated immunity (VZV-CMI) measured by T lymphocyte proliferation assays (using responder cell frequency [RCF] or gamma interferon [IFN-␥] enzyme-linked immunospot [ELISPOT] assays) (10, 21), whereas the level of serum immunoglobulin antibody to VZV remains relatively constant with age (10, 15, 19). These observations suggest that HZ develops in older individuals because their VZV-CMI falls below some critical threshold that is permissive for clinically apparent VZV reactivation. The pivotal trial with the licensed zoster vaccine was based on this assumed relationship (14). This vaccine, zoster vaccine live (Oka/ Merck) (Zostavax; Merck & Co., Inc.), induced VZV-specific antibody and VZV-CMI responses, and the vaccine-induced responses correlated with protection against HZ (10). Zoster vaccine reduced the incidence of HZ and postherpetic neuralgia (PHN) in immunocompetent adults ⱖ 60 years of age and diminished the acute and chronic pain associated with HZ (13). Zoster vaccine also prevents HZ in subjects 50 to 59 years of age, and this effect correlates with the vaccine-induced boost in levels of VZVspecific antibody (reference 15 and unpublished data [Merck]). Understanding the kinetics and age dependence of the VZVCMI responses to clinically apparent reactivation of VZV (i.e., HZ) and their comparability to vaccine-induced VZV-CMI responses is important for understanding the current value and fu- September 2012 Volume 19 Number 9 ture use of the zoster vaccine. This probe study determined the kinetics and variability of VZV-specific IFN-␥ ELISPOT responses in subjects, in two different age cohorts with acute HZ, and compared them to the VZV-CMI of healthy age-matched subjects without HZ. MATERIALS AND METHODS Study population. Healthy subjects ⱖ 60 years of age who had resided in the United States for ⱖ30 years and had not had HZ were eligible for the study. Subjects were excluded if they had previously received any VZVcontaining vaccine, had been exposed to varicella or HZ within 4 weeks prior to study initiation, were immunosuppressed by illness or medical treatments, had a neoplastic disease, had received corticosteroid treatment within the 4 previous weeks, or had received blood products within 3 months prior to enrollment. The protocol was approved by the Ethical Review Committee of each participating site, and written informed consent was obtained from each subject prior to entry into the study. Study design. This was a study conducted at 5 sites within the United States between November 2000 and August 2003 to examine the VZVCMI responses of subjects in the acute or early convalescent phase of HZ. All HZ subjects were clinically diagnosed by the site investigator, and the diagnoses were confirmed by VZV-specific PCR on lesion samples obtained at enrollment (8). The key elements of the diagnosis included a unilateral, dermatomally distributed rash consisting of grouped vesicles Received 21 February 2012 Returned for modification 1 April 2012 Accepted 29 June 2012 Published ahead of print 11 July 2012 Address correspondence to Janie Parrino, . Copyright © 2012, American Society for Microbiology. All Rights Reserved. doi:10.1128/CVI.00095-12 Clinical and Vaccine Immunology p. 1411–1415 cvi.asm.org 1411 Tyring et al. FIG 1 Subject accounting. with signs of inflammation (i.e., erythema) and pain before, during, and/or after the presentation of the rash. If the PCR sample was inadequate, the diagnosis of HZ rested with the site principal investigator. If the PCR sample was confirmed to be negative for VZV, the subject was excluded from all analyses. Enrollment was planned for 50 subjects ⱖ60 years of age and 30 subjects 21 to 59 years of age with HZ, who were seen by the site staff within 72 h of lesion onset. An additional 50 subjects (25 in each age group) presenting with an HZ rash between 4 and 10 days after lesion onset were enrolled. Each cohort of subjects with HZ was matched with an equal number of healthy control subjects by age, race, and gender. Blood samples were drawn at enrollment (day 0) and at 2 weeks, 6 weeks, and 6 months postenrollment to determine the VZV-specific IFN-␥ ELISPOT responses. Immunogenicity measurements. Blood was analyzed for (...truncated)