The cellular receptor for hepatitis B virus (HBV) infection has not yet been identified. The purpose of this study was to address the possibility of participation by desialylated HBV and the asialoglycoprotein receptor (ASGP-R) exclusively expressed on liver parenchymal cells, in infection. Assays for viral binding and entry were performed by culturing a hepatoblastoma cell line, HepG2, and HBV particles derived from the HBV carrier in the presence or absence of neuraminidase (NA). Viral binding and entry were clearly enhanced in the presence of NA, and the enhancement of the binding could be blocked by asialo-fetuin and ethylenediamine-tetraacetic acid (EDTA). In addition, covalently closed circular (CCC)-DNA, as a marker of infectivity, was detected in the presence of NA, but not in its absence. The optimal concentration of NA raised infectivity more than 1000 times. We concluded that this method makes it feasible to evaluate the infectivity of HBV in vitro and that ASGP-R may be a specific HBV receptor once viral particles are desialylated.

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.

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.

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.

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