Herpes simplex virus DNA testing by a loop-mediated isothermal amplification method for accurate clinical diagnosis and detection of mucosal viral shedding.

Herpes simplex virus (HSV) periodically forms characteristic blisters in the perioral and genital areas in a subset of people. Because of the lack of accurate tests for this common virus, various types of perioral/anogenital lesions are often misdiagnosed as herpes. Also, though asymptomatic HSV-positive people shed virus, the precise time course of symptoms and viral shedding is unclear. The loop-mediated isothermal amplification (LAMP) method amplifies target DNA sequences without thermal cycles, simpler and faster than polymerase chain reaction (PCR). To investigate clinico-laboratorial correlation and whether HSV can be detected in the oral cavity during symptom occurrence, we collected 445 specimens from 211 patients who visited our clinic with suspected herpetic lesions or non-symptomatic volunteers. DNA was extracted from swabs simultaneously taken from lesions (n = 219) and seemingly asymptomatic oral mucosa (n = 226). HSV-1 and HSV-2 DNA sequences were amplified by LAMP and validated by quantitative real-time PCR. The LAMP method detected HSV DNA almost as sensitively (97%) as PCR. Positivity for HSV DNA was found in 54% (40/74) of specimens from the perioral/oral area. Review of clinical images of recurrent herpes labialis revealed that HSV DNA was detected only from lesions located on the perioral skin and/or the dry, vermillion part of the lip; no HSV DNA was found in immunocompetent patients with lesions confined to the oral mucosa except primary infection. This observation may be an important principle for clinical diagnosis of recurrent herpes. HSV was detected in the oral mucosa in 2.7% (6/226) of samples; all of these patients had either primary infection or were immunosuppressed. Virus shedding in the mucosa was apparently tightly regulated by the immune system. Patients with suppressed or no immunity (naïve cases) did shed virus in the mucosa. LAMP is a simple method to reliably distinguish recurrent/primary herpes from other conditions.

Relationship between serum anti-varicella zoster virus antibody titer and time from onset of herpes zoster.

Herpes zoster is an internal reactivation of varicella zoster virus, and its onset depends on immunity against this virus. We have previously reported that antiviral antibody titers are inversely correlated with patient numbers. In this study, we hypothesized that patients with higher titers may be late visitors to the clinic, whose antibodies were already boosted at presentation because of the time lapse between onset of zoster and measurement of antibodies. We analyzed antibody titers of patients with acute herpes zoster who visited Fukuoka University Hospital from January 2009 to May 2016 (n = 141, 62 males and 79 females). Varicella zoster virus-specific immunoglobulin G, M and complement fixation tests were positive in 93.9%, 12.0% and 64.2% of the patients, respectively. Immunoglobulin G and complement fixation titers were strongly correlated (Spearman's r = 0.8634, P < 0.0001). Patients with high immunoglobulin G and complement fixation titers were immunoglobulin M-negative. Unexpectedly, immunoglobulin G and complement fixation titers showed large inter-subject variation, and were only weakly correlated with onset-measurement time lapse. Patients with consecutive tests tended to show increasing immunoglobulin G and complement fixation titers. Our data suggest that herpes zoster preferentially occurs in patients with low immunoglobulin G and complement fixation titers, and subsequently causes antibody elevation. However, the timing of elevation varies and can be as late as 10 days after zoster. The large variation in antibody titer over the time from onset to testing suggests that some mechanism exists that resists the local breakthrough of virus in the skin, and so delays the onset of blisters.

Incidence of serum antibody titers against herpes simplex virus in Japanese patients.

Herpes simplex virus (HSV) establishes latency in the sensory neuronal ganglia after primary infection, and occasionally causes recurrent infection, mainly on the lips or genitalia. Previous reports revealed an age-related increase in HSV-immunoglobulin G seropositive subjects in a hospital-based study and the general population in Japan. In this report, we retrospectively analyzed the results of serological tests against HSV, in which subjects were diagnosed with or suspected as having HSV infection. A total of 1216 subjects with at least one complement fixation (CF) result were included. Of these, 771 subjects (63.4%) were positive at first visit. When stratified by age, incidence of positive patients linearly increased with age from teenagers (44.9%) to those in their 80s (88.9%). Positivity in women was higher than in men overall; significantly higher incidence was observed in women aged in their 30s, 40s and 60s. When observing changing HSV-CF titers over time in 81 initially negative patients, 18 (22%) seroconverted during the 2121-day observation period. In this study, we clearly show that distribution of HSV-CF titers is similar to previous HSV-immunoglobulin G results. This correlation is probably caused by the continual subclinical proliferation of HSV, thus maintaining CF titers. Our observations provide current data on the incidence of HSV, reconfirming that serological examination is unreliable in diagnosing recurrent herpes, and the majority of infected subjects are asymptomatic.

Incidence of serum antibody titers against varicella zoster virus in Japanese patients with herpes zoster.

Herpes zoster is an internal reactivation of varicella zoster virus following establishment of latent infection in the dorsal root ganglia during primary infection, which presents as chickenpox. Therefore, serologically, herpes zoster patients already have anti-varicella zoster virus immunoglobulin G at the onset of disease. Hence, positive serum antibody does not confirm the diagnosis of herpes zoster. We retrospectively investigated the incidence of varicella zoster virus-specific complement fixation in 865 zoster patients at initial presentation to a dermatology clinic. As a result, 66% of patients showed negative complement fixation, with patient numbers decreasing as titer increased. Paired complement fixation tests conducted within a short period showed a marked elevation in titer, and complement fixation titer gradually decreased after a year. Furthermore, incidence showed no correlation with patient age. These observations indicate that the complement fixation titer at first visit is mainly influenced by the duration from onset to presentation at clinic. Our findings indicate that a positive complement fixation result by single-point testing confirms at least recent onset of herpes zoster, while paired tests can confirm disease when primary tests are negative.

Relationship between prior knowledge about herpes zoster and the period from onset of the eruption to consultation in patients with herpes zoster.

Herpes zoster (HZ) is a common internal infection caused by latent varicella zoster virus. Emergence of antiviral chemotherapy has changed the treatment of HZ dramatically, but the effects of such therapy are documented only in patients who started treatment within 72 h of HZ onset of the eruption. There have been few studies addressing the question of factors that determine early attendance of patients at a clinic. We questioned 256 patients with acute HZ about: (i) date from onset of the eruption to first clinic visit; and (ii) their prior knowledge of HZ. We found a tendency that patients who already knew about HZ had consulted dermatology clinics earlier (P < 0.05). People most commonly obtained information about the disease from friends and family members who had previously had HZ, but not from the Internet or other mass media. Our results indicate that patient education is important for early attendance at dermatology clinics, which in turn, should result in the improved outcome of antiviral chemotherapy and prevention of postherpetic neuralgia.