Charles Wohlenberg

Prevention of ultraviolet-light-induced herpes labialis by sunscreen

Sunlight exposure is reported by some patients to precede onset of recurrent herpes labialis. Ultraviolet (UV) B light is known to be a stimulus for the reactivation of herpes simplex virus (HSV) infections. We assessed the effect of a sunblocking agent on UV-light-induced reactivation of recurrent herpes labialis in a double-blind, placebo-controlled crossover trial. 38 patients were exposed on two separate occasions to four minimum erythema doses of UV light at an area of previous labial herpes recurrence. A solution containing sunscreen was applied to the lips before one exposure and a matched placebo before the other. After placebo and UV exposure, herpes labialis developed in 27 (71%) of the 38 patients, with a mean time to recurrence of 2.9 (SEM 0.2) days. In contrast, when sunscreen was applied before UV exposure, no lesions developed, but 1 of the 35 patients shed virus at the exposure site. We conclude that UV light is a potent stimulus for inducing reactivation of herpes labialis, and that application of sunscreen may be effective in the prevention of sunlight-induced recurrent infection.

Acute and latent infection of sensory ganglia with herpes simplex virus: immune control and virus reactivation.

The role of antiviral antibody in controlling the acute and latent phases of herpes simplex virus (HSV) infection in sensory ganglia of mice was studied in vitro and in vivo. Organ cultures of ganglia inoculated in vitro with HSV produced infectious virus for at least 3 weeks. In the presence of antiviral antibody, the titre of virus was markedly reduced, but the infection was not eliminated. Similarly, passive administration of antibody to HSV-infected immunodeficient (nude) mice reduced the virus titre but did not eliminate the acute phase of the ganglionic infection. Suppression of the cell-mediated immune response in latently infected immunocompetent mice by treatment with cyclophosphamide and/or X-irradiation resulted in reactivation of HSV in up to 70% of the animals. Reactivation was demonstrated by recovering infectious virus in cell-free homogenates of ganglia and eye globes and by finding virus antigens in ganglia by immunofluorescent staining. Reactivation occurred both in vitro and in vivo in the presence of high concentrations of neutralizing antibody. It is concluded that antibody alone is not sufficient to eliminate the acute phase of the ganglionic infection and that cytotoxic agents known to suppress the hosts cellular immune response can reactivate virus in the presence of neutralizing antibody.

Oral Acyclovir To Suppress Frequently Recurrent Herpes Labialis: A Double-Blind, Placebo-Controlled Trial

Recurrent herpes simplex labialis affects nearly one third of the population of the United States, with an annual incidence estimated at 100 million episodes [1]. In immunocompetent patients, most of these episodes are mild and self-limited. Nonetheless, patients often report pain, swelling, and cosmetic concerns associated with recurrent episodes and fear of transmitting herpes simplex virus (HSV) to others. Although most patients with recurrent herpes labialis have fewer than two episodes yearly, a small percentage of patients (5% to 10%) report frequent recurrences, defined as six or more episodes yearly. Antiviral medications have not proved reliably effective in treating herpes labialis when administered at the onset of symptoms [2]. Acyclovir, when given prophylactically in daily doses, however, has proved effective in suppressing recurrent herpes labialis in the immunocompromised host [3-6] and in the short-term ( 14 days) prevention of herpes labialis in the immunocompetent host [7-9]. The efficacy of acyclovir in long-term suppression of herpes labialis has yet to be documented. Administration of daily oral acyclovir for up to 7 years in patients with recurrent genital herpes without significant adverse consequences has been shown [10-13]. Our investigation was initiated to determine in a placebo-controlled trial whether daily oral acyclovir would prove effective in reducing the incidence of herpes labialis in otherwise normal persons documented to have unusually frequent outbreaks. Methods Study Sample Patients were enrolled at the outpatient facilities of the Warren Grant Magnuson Clinical Center of the National Institutes of Health, Bethesda, Maryland, from February 1988 to March 1990. Otherwise healthy adults, ages 18 to 50, who reported histories of 6 or more episodes of herpes labialis per year were eligible for entry into the study. Patients with child-bearing potential were required to practice effective methods of birth control, and women were required to have a negative pregnancy test. Study Design At the initial clinic visit informed consent was obtained, a history and physical examination were done, and blood and urine samples were obtained for routine hematology, blood chemistry tests, urinalysis, and urine pregnancy testing as well as for HSV serology testing. Patients then began a 4-month observation period to document the frequency of recurrent herpes labialis because it was felt that only in patients with frequent recurrences would treatment with daily oral acyclovir be justified. Those patients who had two or more recurrences (at least one of which was confirmed by culture) during the observation period were randomized to receive either acyclovir, 400 mg twice daily, or matched placebo (provided by Burroughs Wellcome Company, Research Triangle Park, North Carolina) for 4 months (treatment course A) and then switched to the opposite therapy for another 4 months (treatment course B). Study medication was then discontinued, and patients were followed to first recurrence of herpes labialis. During all study phases patients were seen in clinic at monthly intervals and were questioned regarding signs or symptoms of recurrent disease and medication compliance. Urine pregnancy testing was done monthly for women of child-bearing potential, and routine hematologic and blood chemistry testing was done on all patients at 4-month intervals. In addition, patients were instructed to return to clinic within 24 hours of the onset of an outbreak of herpes labialis. Recurrent disease was documented by physical examination, viral culture, and photography. Patients were also instructed to keep home records in which they documented the onset, duration, and location of all outbreaks and noted any missed medication. Viral Studies Specimens obtained by aspiration or swabbing of suspected lesions were transported in veal infusion broth on ice to the laboratory. Roller tubes containing human diploid fibroblasts or rabbit kidney cells, or both were inoculated in duplicate with 0.2 mL of the lesion material and were observed for 14 days for cytopathic effects indicative of HSV infection. Positive cultures were typed using fluorescein-labeled monoclonal antibodies specific for HSV-1 or HSV-2 (Syva Microtrak, Syva Company, Palo Alto, California). Antiviral sensitivity analysis was carried out on selected isolates using a radiolabeled probe to quantify viral DNA (Hybriwix HSV Antiviral Susceptibility Test Kit, Diagnostic Hybrids, Inc., Athens, Ohio). Study Definitions Documentation of a recurrence was determined by clinical examination and viral culture of suspected lesions. Clinical documentation was based on observation of crusts, vesicles, or grouped lesions in any stage, occurring in an anatomic area appropriate for recurrent herpes labialis. Any suspected lesion whose viral culture was scored as positive was considered virologically documented. The duration of a recurrence was defined as the time to complete healing. Statistical Methods In keeping with the crossover design of the study, paired analyses were used to assess the efficacy of treatment. Thus, a paired-sample t-test was applied to the respective differences between the number of recurrences on placebo and the number on acyclovir; also, a sign test [14] was applied to the corresponding proportions of episodes with virus culture-positive lesions. A McNemar test [14] was used to compare the number of patients who had a recurrence on placebo but not on acyclovir with the number who had a recurrence on acyclovir but not placebo. Analysis of the time to first recurrence on each treatment was complicated by two features of these data: censoring at the end of the treatment period (about 120 days) and the unexplained finding that virologically determined recurrence times on placebo were significantly longer among patients in course B than among patients in course A. The first feature introduced doubly censored within-patient treatment differences that led to the use of a modified Gehan test [15] applied to between course differences classified according to identity of the first course treatment. The second feature required that virologically determined course B recurrence times be eliminated; an ordinary Gehan test [16] was applied to the course A virologically determined recurrence times for acyclovir and placebo recipients. Analysis of duration of recurrences on acyclovir compared with placebo treatment was made using a paired-sample t-test. Carryover effects were obviated by excluding from data analysis recurrences observed during the first week of each of the four study periods, as stipulated by the study protocol. Results Fifty-six patients entered into the pretreatment observation phase of this study. Twenty-two patients had two or more recurrences of herpes labialis and were randomized into two groups to receive study medication. The demographic and clinical characteristics of these groups are shown in Table 1. Patients in the first group received acyclovir for treatment course A and placebo for treatment course B, whereas patients in the second group received these medications in the reverse order. Two patients from the first group dropped out of the study, one because of headache and nausea after receiving five doses of acyclovir in treatment course A and one for administrative reasons after successfully completing the course of acyclovir. These patients were excluded from final analysis. An additional patient from the first group had nausea, vomiting, and diarrhea, attributed to gastroenteritis, during month 2 of acyclovir therapy on treatment course A, and study medication was discontinued for 1 day. When therapy was resumed, no adverse effects were noted, and the data from this patient were included in the final evaluation. Study medication was otherwise well tolerated by all patients. According to patient home records, 99% of prescribed study medication was taken during both acyclovir and placebo treatments. Table 1. Pretreatment Demographic and Clinical Characteristics of Patients with Recurrent Herpes Labialis Who Received Treatment with Acyclovir or Placebo Effect of Therapy Twenty patients completed treatment with both acyclovir and placebo, and the paired analysis of the data from these patients was used to evaluate treatment effect. Treatment with acyclovir resulted in a greater than 2.5-fold prolongation in the median time to first clinically determined recurrence (46 to 118 days, P = 0.05) and time to first virologically determined recurrence (46 to > 118 days, P = 0.002) (Table 2). Table 2. Effect of Treatment in 20 Patients Who Completed Therapy with Acyclovir and Placebo* Acyclovir therapy also resulted in a 53% reduction in the mean number of clinically documented recurrences per 4-month period of treatment (1.80 to 0.85 episodes per patient, P = 0.009) and a 71% reduction in the mean number of culture-positive recurrences (1.40 to 0.40 episodes per patient, P = 0.003) (Table 2). Seventeen patients had a total of 36 clinically confirmed recurrences of herpes labialis while on placebo treatment, whereas 10 patients on acyclovir therapy had a total of 17 recurrences (P = 0.03 for comparison of patients having recurrence on placebo but not acyclovir [n = 9] compared with those having recurrence on acyclovir but not placebo [n = 1]). Sixteen patients on placebo had virologically confirmed recurrences, whereas only six did on acyclovir (P < 0.01 for comparison of patients experiencing recurrence on placebo but not acyclovir [n = 11] compared with those with recurrence on acyclovir but not on placebo [n = 1]). Although not designed to do so optimally, this study permitted some assessment of the duration of lesions based on patient home records. There was an apparent reduction in the mean ( SE) duration of lesions to 4.3 0.9 days during acyclovir therapy compared with 7.9 1.6 days for recurrences that developed while on placebo (P = 0.11;

Different Sizes of Restriction Endonuclease Fragments from the Terminal Repetitions of the Herpes Simplex Virus Type 1 Genome Latent in Trigeminal Ganglia of Mice

Trigeminal ganglion DNA from mice latently infected with herpes simplex virus type 1 was analysed by restriction enzyme digestion, agarose gel electrophoresis and blot hybridization to 32P-labelled viral DNA. Viral DNA from parental virions and from virions obtained as a consequence of reactivation by ganglion neurectomy were similarly analysed. The BamHI restriction fragments of parental and reactivated virions were almost indistinguishable from each other, and several of the larger BamHI fragments of viral DNA were also found in latently infected ganglion at unaltered sizes. In contrast, fractionation of EcoRI fragments of latently infected ganglion DNA by reverse phase column (RPC-5) chromatography, followed by gel electrophoresis and blot hybridization to a viral DNA probe from the S component terminal repetition, revealed the presence of several terminal fragments at discrete sizes ranging from 1 kb to 15 kb, quite unlike the 5.7 kb terminal EcoRI K fragment of virion-derived DNA. These results indicate that structural changes occur in the viral genome concomitantly with the establishment of latency, such as may result from extensive gene rearrangement or integration into cellular DNA.

In Vitro System for Studying the Efficacy of Antiviral Agents in Preventing the Reactivation of Latent Herpes Simplex Virus

Antiviral antibody and interferon did not prevent in vitro reactivation of herpes simplex virus in latently infected sensory ganglia. Phosphonoacetic acid and 9-β-d-arabinofuranosyladenine blocked reactivation, but this treatment did not eradicate the latent infection.