Karen E. Mark

Rapidly cleared episodes of herpes simplex virus reactivation in immunocompetent adults

BACKGROUND Herpes simplex virus (HSV) remains latent in nerve root ganglia of infected persons and is thought to reactivate several times yearly. Recent in situ data show the localization of HSV-specific CD8(+) T cells at the dermal epidermal junction next to peripheral sensory nerve endings, suggesting that viral reactivation may occur more frequently than previously appreciated. METHODS Twenty-five HSV-2-seropositive and 18 HSV-1-seropositive healthy adults collected anogenital and oral swabs, respectively, 4 times per day for 60 days. Swabs were assayed for HSV, using a quantitative polymerase chain reaction assay. RESULTS Twenty-four percent of anogenital reactivations and 21% of oral reactivations lasted < or =6 h, and 49% of anogenital reactivations and 39% of oral reactivations lasted < or =12 h. Lesions were reported in only 3 (7%) of 44 anogenital reactivations and 1 (8%) of 13 oral reactivations lasting < or =12 h. The median HSV DNA levels at initial and last detection were 10(3.5) and 10(3.3) copies/mL, respectively, during anogenital reactivation and 10(3.7) and 10(3.0) copies/mL, respectively, during oral reactivation. CONCLUSIONS This high frequency of short subclinical HSV reactivation in immunocompetent hosts strongly suggests that the peripheral mucosal immune system plays a critical role in clearing HSV reactivations.

Topical resiquimod 0.01% gel decreases herpes simplex virus type 2 genital shedding: A randomized, controlled trial

BACKGROUND Resiquimod, an investigational immune response modifier and Toll-like receptor (TLR) 7 and 8 agonist, stimulates production of cytokines that promote an antigen-specific T helper type 1 (Th1)--acquired immune response. In animal models, induction of Th1-specific responses modifies experimental herpes simplex virus (HSV) infection. METHODS We conducted a randomized, double-blind, vehicle-controlled trial to assess the efficacy of resiquimod 0.01% gel for reducing human anogenital HSV-2 mucosal reactivation. Adults with genital HSV-2 applied resiquimod or vehicle topically to herpes lesions 2 times weekly for 3 weeks and then collected daily anogenital swabs for 60 days for HSV DNA polymerase chain reaction. Recurrences during the subsequent 7 months were treated with study gel. During the final treatment-free 60 days, participants again collected daily swabs to assess shedding. RESULTS The median lesion and shedding rates were lower for resiquimod compared with vehicle recipients during the initial sampling period (10% vs. 16% [P=.03] and 10% vs. 17% [P=.08], respectively) and during the final sampling period (3% vs. 22% [P<.001] and 10% vs. 26% [P=.009], respectively). Resiquimod did not influence recurrence length. CONCLUSIONS These findings suggest that the immunological control of HSV-2 reactivation and lesion clearance may differ and that TLR7 and TLR8 agonists can reduce the frequency of mucosal HSV-2 reactivation.

Mucosal host immune response predicts the severity and duration of herpes simplex virus-2 genital tract shedding episodes

Herpes simplex virus-2 (HSV-2) shedding episodes in humans vary markedly in duration and virologic titer within an infected person over time, an observation that is unexplained. To evaluate whether host or virological factors more closely accounted for this variability, we combined measures of viral replication and CD8+ lymphocyte density in genital biopsies, with a stochastic mathematical model of HSV-2 infection. Model simulations reproduced quantities of virus and duration of shedding detected in 1,003 episodes among 386 persons. In the simulations, local CD8+ lymphocyte density in the mucosa at episode onset predicted peak HSV DNA copy number and whether genital lesions or subclinical shedding occurred. High density of CD8+ T cells in the mucosa correlated with decreased infected cell lifespan and fewer infected epithelial cells before episode clearance. If infected cell lifespan increased by 15 min because of CD8+ lymphocyte decay, then there was potential for a thousandfold increase in the number of infected cells. The model suggests that the rate of containment of infected cells by the peripheral mucosal immune system is the major driver of duration and severity of HSV-2 reactivation in the immunocompetent host.

Frequent Release of Low Amounts of Herpes Simplex Virus from Neurons: Results of a Mathematical Model

A stochastic mathematical model suggests that very low numbers of herpes simplex virus 2 particles are released frequently into the genital tract in infected individuals. Insights from Modeling Herpes Virus Behavior One variety of the herpes simplex virus (HSV-2) infects 45 million people worldwide, often causing ulcers in the genital region, and increases the acquisition and transmission of HIV. Herpes is passed from person to person through sexual contact. After the initial infection, the herpes virus resides in the cell bodies of neurons that innervate the genital tract, sometimes causing recurrences of the painful genital blisters. With newer, highly sensitive methods of detecting the virus by the polymerase chain reaction, the pattern of HSV-2 shedding in the genital tract was unexpectedly revealed to include frequent, intermittent episodes of variable amounts of virus, not just the periodic larger episodes that had been assumed to cause the sporadic recurrence of genital ulcers. This finding has been of concern for several reasons: The likelihood of transmitting the virus to a sexual partner is higher if herpes virus is often present in the genital tract of infected people. And worse, most episodes of release of the small amounts of virus are not accompanied by any symptoms, so infected individuals are often unaware of their own infectious state. A clearer understanding of how virus release into the genital tract is controlled and when it causes an active ulcer is needed to develop better ways to combat this common infection. Available treatments, mainly antiviral agents, can only limit spread and accelerate healing but do not completely eliminate asymptomatic shedding or transmission. Because informative experiments are difficult to do in humans, Schiffer et al. developed a mathematical model of HSV-2 infection of mucosal tissue. Their model—which incorporated virus release to the genital mucosal tissue, infection of epithelial cells, replication of virus within epithelial cells, and an immune response—faithfully replicated shedding episode data from anogenital swabs from 89 patients and from lesions of 15 more patients. It predicted that infected epithelial cells can generate hundreds of times more virus than the infected neurons, accounting for detectable shedding episodes. A stochastic version of the model predicted variability in the patterns of herpes infection seen in patients with respect to the percentage of time spent shedding and the lesion diameter. The model also suggested that there are many clinical episodes of viral shedding that cannot be detected by current methods. Most important, the analysis led the authors to conclude that neurons releasing only a few copies of herpes virus each day can cause the characteristic periodic outbreaks of painful ulcers and that it is the amount of virus released per unit time, not the frequency of release, that controls how often detectable virus appears in the genital tract. The authors used both patient data and the cellular biology of herpes infection to build an informative model that has revealed a control point for a key determinant of viral infectivity, suggesting a vulnerable target for therapeutic intervention. Herpes simplex virus 2 (HSV-2), a sexually transmitted infection, is the leading cause of genital ulcers worldwide. Infection is lifelong and is characterized by repeated asymptomatic and symptomatic episodes of virus shedding that are initiated when virus is released from neurons into the genital tract. The pattern of HSV-2 release from neurons, which harbor the virus, into the genital tract is poorly understood. We fit a mathematical model of HSV-2 pathogenesis to curves generated from daily quantification of HSV in mucosal swabs from patients with herpetic genital ulcers. We used virologic parameters derived from model fitting for stochastic model simulations. These simulations reproduced previously documented estimates for shedding frequency and herpetic lesion diameter and frequency. The most realistic model output occurred when we assumed that the amount of virus shed from neurons daily was minimal. In our simulations, small changes in the average total quantity of HSV-2 released from neurons influenced the frequency of detectable shedding, whereas changes in the frequency of HSV-2 neuronal release had little effect. Frequent HSV-2 shedding episodes in humans are explained by nearly constant release of small numbers of viruses from neurons that terminate in the genital tract.

Rapid localized spread and immunologic containment define Herpes simplex virus-2 reactivation in the human genital tract

Herpes simplex virus-2 (HSV-2) is shed episodically, leading to occasional genital ulcers and efficient transmission. The biology explaining highly variable shedding patterns, in an infected person over time, is poorly understood. We sampled the genital tract for HSV DNA at several time intervals and concurrently at multiple sites, and derived a spatial mathematical model to characterize dynamics of HSV-2 reactivation. The model reproduced heterogeneity in shedding episode duration and viral production, and predicted rapid early viral expansion, rapid late decay, and wide spatial dispersion of HSV replication during episodes. In simulations, HSV-2 spread locally within single ulcers to thousands of epithelial cells in <12 hr, but host immune responses eliminated infected cells in <24 hr; secondary ulcers formed following spatial propagation of cell-free HSV-2, allowing for episode prolongation. We conclude that HSV-2 infection is characterized by extremely rapid virological growth and containment at multiple contemporaneous sites within genital epithelium. DOI: http://dx.doi.org/10.7554/eLife.00288.001

Rapidly cleared episodes of oral and anogenital herpes simplex virus shedding in HIV-infected adults

Objective:To determine whether rapidly cleared episodes of herpes simplex virus (HSV) reactivation occur in HIV-infected adults. Methods:Twenty HSV-2-seropositive, HIV-seropositive adults, including 9 (45%) who were also HSV-1 seropositive, collected oral and anogenital swabs for HSV DNA polymerase chain reaction 4 times a day for 60 days. Samples were positive for HSV if we detected ≥150 copies of HSV DNA/mL of specimen. Results:Median HSV shedding episode duration was 7.5 (range 4-253) hours for oral and 11 (range 4-328) hours for anogenital reactivation. Thirty-five percent of oral and 29% of anogenital reactivations lasted ≤6 hours, and 59% of oral and 53% of anogenital reactivations lasted ≤12 hours. Seven of 9 participants who shed orally and 10 of 15 who shed anogenitally had ≥1 reactivation lasting ≤6 hours. The median maximum level of HSV DNA detected in an episode increased with episode duration for both oral and anogenital episodes. Concurrent oral and anogenital shedding occurred more frequently than expected: oral HSV shedding was detected on 17% of time points with anogenital but 1% of time points without anogenital, shedding (P < 0.001). Conclusions:Rapidly cleared episodes of oral and anogenital HSV shedding occur in HIV-infected persons, supporting the hypothesis that frequent anogenital mucosal immune activation caused by HSV-2 is present in HIV coinfected persons, potentially contributing to HIV infectiousness.

Internet and email use among STD clinic patients

Background: Little data exist on Internet and email use among STD clinic patients for research and clinical care communication. Methods: An anonymous cross-sectional survey of STD clinic patients aged ≥18 years in Seattle, WA, March 13 to 22, 2006. Results: Of 489 study period patients, 251 (51%) completed the questionnaire. Participants had a median age of 30 (range 18–66) years and were 69% male, 56% white, 19% black, 9% Hispanic, and 7% Asian/Pacific Islander. Of all participants, 75% had some postsecondary education but half reported an annual income of <US

Peripheral Blood CD4 T-Cell and Plasmacytoid Dendritic Cell (pDC) Reactivity to Herpes Simplex Virus 2 and pDC Number Do Not Correlate with the Clinical or Virologic Severity of Recurrent Genital Herpes

15,000. Of 251 participants, 200 (80%) reported using the Internet from a private location at least once a week, 190 (76%) had their own email that they check at least 3 times a week, and 144 (57%) were willing to receive an email reminding them to come back for a follow-up appointment if diagnosed with an STD. Men who have sex with men were more likely than women and heterosexual men to be regular Internet and email users (92% vs. 70%, P = 0.001) and to have met a sex partner over the Internet during the past year (69% vs. 11%, P <0.001). Higher educational level and income, but not age or gender, were also associated with Internet and email use, as was racial/ethnic background (86% of whites, 48% of blacks, 73% of Hispanics, 100% of Asians/Pacific Islanders, and 57% of others, P <0.001). Conclusions: Internet and email use are common and acceptable to many STD clinic patients for research and clinical purposes.

Medical Care and Alcohol Use after Testing Hepatitis C Antibody Positive at STD Clinic and HIV Test Site Screening Programs

ABSTRACT Leukocytes participate in the immune control of herpes simplex virus (HSV). Data from HIV coinfections, germ line mutations, and case reports suggest involvement of CD4 T cells and plasmacytoid dendritic cells (pDC). We investigated the relationships between these cells and recurrent genital herpes disease severity in the general population. Circulating CD4 T-cell responses to HSV-2 were measured in specimens from 67 immunocompetent individuals with measured genital lesion and HSV shedding rates. Similarly, pDC number and functional responses to HSV-2 were analyzed in 40 persons. CD4 responses and pDC concentrations and responses ranged as much as 100-fold between persons while displaying moderate within-person consistency over time. No correlations were observed between these immune response parameters and genital HSV-2 severity. Cytomegalovirus (CMV) coinfection was not correlated with differences in HSV-2-specific CD4 T-cell responses. The CD4 T-cell response to HSV-2 was much more polyfunctional than was the response to CMV. These data suggest that other immune cell subsets with alternate phenotypes or anatomical locations may be responsible for genital herpes control in chronically infected individuals.

Three Phase III Randomized Controlled Trials of Topical Resiquimod 0.01-Percent Gel To Reduce Anogenital Herpes Recurrences

Objectives. The Centers for Disease Control and Prevention recommend screening individuals at risk for hepatitis C virus (HCV) infection. However, few published data describe outcomes of individuals with antibody to HCV (anti-HCV) identified through screening programs. The purpose of this study was to assess rates of medical evaluation and HCV treatment, change in alcohol consumption, and barriers to medical care after testing anti-HCV positive through a public screening program. Methods. Anti-HCV positive individuals identified through San Diego sexually transmitted disease (STD) clinics and an HIV test site screening program were informed of positive test results, provided education and referral, and contacted by telephone three, six, and ≥12 months later. Results. From September 1, 1999, to December 31, 2001, 411 anti-HCV positive individuals were newly identified, of whom 286 (70%) could be contacted ≥ three months after receipt of test results (median length [range] of follow-up 14 [3–35] months). Of these 286, 156 (55%) reported having received a medical evaluation, of whom 19 (12%) began HCV treatment. Of 132 who reported drinking alcohol before diagnosis, 100 (76%) reported drinking less after diagnosis. Individuals with medical insurance at diagnosis were more likely than those without insurance to obtain a medical evaluation during follow-up (75 [68%] of 111 vs. 70 [45%] of 155; p<0.001). Among those who did not obtain an evaluation, the most commonly reported reason was lack of insurance. Conclusions. Only about half of newly identified anti-HCV positive individuals received a medical evaluation, although 76% reported drinking less alcohol. Identifying ways to improve medical access for those who are anti-HCV positive could improve the effectiveness of screening programs.