Associations between tobacco smoking status and patch test results-A cross-sectional pilot study from the Information Network of Departments of Dermatology (IVDK).

BACKGROUND: Earlier studies suggested a potential association between tobacco smoking and nickel sensitization, but little is known about other contact allergens. OBJECTIVES: To investigate the association of smoking status and contact sensitizations as well as subtypes of dermatitis, and to analyse the sensitization profiles of tobacco smokers. PATIENTS AND METHODS: Within the Information Network of Departments of Dermatology (IVDK), we performed a cross-sectional multicentre pilot study comprising 1091 patch-tested patients from 9 departments, comparing 541 patients with a history of cigarette smoking (281 current and 260 former smokers) with 550 never-smokers. RESULTS: We could not confirm the previously reported association between nickel sensitization and tobacco smoking. Moreover, sensitizations to other allergens, including colophony, fragrance mix I, Myroxylon pereirae and formaldehyde, were not increased in cigarette smokers compared with never smokers. Hand dermatitis (50.6% vs. 33.6%) and occupational cause (36.2% vs. 22.5%) were significantly more frequent among cigarette smokers compared with never-smokers as shown by non-overlapping 95% confidence intervals. CONCLUSIONS: Although our study does not allow a firm conclusion on whether smoking status contributes to certain contact sensitizations, it confirms an association of smoking with hand dermatitis and occupational cause.

Severely compromised supply of patch test allergens in Europe hampers adequate diagnosis of occupational and non-occupational contact allergy. A European Society of Contact Dermatitis (ESCD), European Academy of Allergy and Clinical Immunology (EAACI), European Academy of Dermatology and Venereology (EADV) task forces 'Contact Dermatitis' and 'Occupational Skin Disease' position paper.

Patch testing is the only clinically applicable diagnostic method for Type IV allergy. The availability of Type IV patch test (PT) allergens in Europe, however, is currently scarce. This severely compromises adequate diagnostics of contact allergy, leading to serious consequences for the affected patients. Against this background, the European Society of Contact Dermatitis (ESCD) has created a task force (TF) (i) to explore the current availability of PT substances in different member states, (ii) to highlight some of the unique characteristics of Type IV vs. other allergens and (iii) to suggest ways forward to promote and ensure availability of high-quality patch testing substances for the diagnosis of Type IV allergies throughout Europe. The suggestions of the TF on how to improve the availability of PT allergens are supported by the ESCD, the European Academy of Allergy and Clinical Immunology, and the European Academy of Dermatology and Venereology and intend to provide potential means to resolve the present medical crisis.

Quality of patch testing patient's own material in patients with suspected occupational skin diseases throughout Germany: Interim results of the German Social Accident Insurance (DGUV) research project FB 317b.

BACKGROUND: Due to limited availability of commercial test preparations, patch testing patient's own material (POM) is of great importance to diagnose occupational allergic contact dermatitis. OBJECTIVES: To assess the quality of performance and documentation of patch testing with POM in patients with suspected occupational skin diseases (OSD) in Germany. METHODS: Retrospective-prospective analysis of protocols of patch tests with POM was conducted between 2013 and 2021 in patients with suspected OSD and submitted to statutory accident insurance institutions. Assessments were done by predefined criteria. RESULTS: Three thousand and four patch tests with POM from 460 patients were included. A full description of the POM was provided in 73.3% of all tests. The test concentration, test vehicle and pH value were documented in 74.3%, 70.5% and 42.2% of tests, for which the respective parameters were considered relevant. One hundred and sixty-one positive reactions to POM were documented. In 72%, sufficient patch testing with commercial test substances was conducted to investigate the positive reaction. In 30.4%, consecutive patch testing of all ingredients of the POM was done. CONCLUSIONS: The results not only show considerable shortcomings mainly in documentation but also to some extent performance of patch tests with POM in patients with suspected OSD in Germany.

Stratum corneum biomarkers after in vivo repeated exposure to sub-erythemal dosages of ultraviolet radiation in unprotected and sunscreen (SPF 50+) protected skin.

BACKGROUND: There is a need for non-invasive biomarkers to assess in vivo efficacy of protective measures aiming at reducing ultraviolet radiation (UVR) exposure. Stratum corneum (SC) biomarkers showed to be promising markers for internal UVR dose and immune response. PURPOSE: To establish a dose-response relationship for SC biomarkers and explore their suitability for in vivo assessment of the blocking effect of two sunscreens with a high sun protection factor (SPF) (50+). METHODS: Twelve volunteers were exposed to a broad-spectrum UVB (280-320 nm), five times a week, during one week. Unprotected back skin was irradiated with 0.24, 0.48, 0.72 and 1.44 standard erythema dose (SED) and sunscreen-protected skin with 3.6 SED. SC samples for determination of the relative amount of cis-urocanic acid (cUCA) and thirteen immunological makers including cytokines and matrix metalloproteinases (MMP) were collected after each irradiation. RESULTS: cUCA sharply increased after the first irradiation in a dose-dependent fashion. However, it levelled-off after subsequent exposures and reached a plateau for the highest UV-dose after the third irradiation. None of the immunological markers showed dose-dependency. However, MMP-9, IL-1ß and CCL27 increased gradually from baseline during repetitive exposures to the highest UV-dose. Assessed from cUCA, both sunscreens blocked >98% of the applied UV-dose. CONCLUSIONS: cUCA is a sensitive, non-invasive marker of the internal UVR dose enabling in vivo assessment of the blocking effect of high SPF sunscreens in the UVB-region. Immunological SC markers show low sensitivity in detecting immune response at sub-erythemal UVR dosages, suggesting they might be suitable only at higher and/or repetitive UVR exposure.

Treatment with alitretinoin in patients taking part in a tertiary individual prevention program for work-related skin diseases.

BACKGROUND: Patients taking part in a tertiary individual prevention program (TIP) for work-related skin diseases frequently have chronic hand eczema (HE) for which alitretinoin is a treatment option. OBJECTIVE: To investigate treatment with alitretinoin before and during the TIP and related factors. METHODS: Data of 1614 patients taking part in the TIP between January 2015 and December 2019 were analyzed retrospectively. RESULTS: Three hundred forty-eight patients (21.6%) reported treatment with alitretinoin prior to the TIP showing an increase over time, particularly in men. In 45 patients (2.8%), alitretinoin treatment was initiated during the TIP. Treatment with alitretinoin was significantly less common among female than male patients, both prior to (P < .001) and during the TIP (P = .015). Female patients who had received alitretinoin in the past were significantly older than the other female patients (P < .001). Among patients treated with alitretinoin prior to the TIP, women had a significantly higher disease severity at admission than men (P = .007). CONCLUSIONS: About twenty percent of patients reported treatment with alitretinoin prior to the TIP. The data indicate that treatment of female TIP patients with alitretinoin is less frequent than among male patients and depends on age and disease severity.

Effectiveness of secondary prevention in metalworkers with work-related skin diseases and comparison with participants of a tertiary prevention program: A prospective cohort study.

BACKGROUND: In Germany, a multistep approach has been established to prevent work-related skin diseases (WRSDs). OBJECTIVES: To evaluate the effect of a secondary individual prevention program (SIP) in metalworkers with WRSD and to compare their characteristics with those of participants of a tertiary individual prevention program (TIP). PATIENTS AND METHODS: In a prospective cohort study, metalworkers with WRSD of the hands participating either in the SIP (n = 114) or in the TIP (n = 83) were recruited. At baseline and at the respective follow-up 8-12 weeks after the SIP or at dismissal from the TIP (3-4 weeks later), questionnaires were completed and the severity of WRSD was assessed. Saliva samples were collected for assessment of filaggrin (FLG) mutations and an explorative genome-wide association study (GWAS). RESULTS: Ninety-three SIP patients (81.6%) attended the follow-up. Disease severity was significantly reduced, and knowledge and protective behavior were significantly improved compared to baseline. Significant differences between SIP and TIP patients were found regarding duration and severity of symptoms, work absenteeism, tobacco smoking, and presence of atopic dermatitis, but not regarding FLG mutations and by GWAS. CONCLUSIONS: The SIP was effective in metalworkers with WRSDs. Individual factors may influence the course of the disease and the need for the TIP.

Health education decreases incidence of hand eczema in metal work apprentices: Results of a controlled intervention study.

BACKGROUND: Metal work apprentices (MWAs) frequently develop work-related hand eczema (HE). OBJECTIVES: To evaluate the effect of health education on incidence of work-related HE in MWAs and to assess confounding factors. MATERIALS/METHODS: In a prospective controlled intervention study, 131 MWAs received educational training on prevention of HE, whereas 172 MWAs and 118 office work apprentices served as controls. At baseline and during three yearly follow-ups, questionnaires were completed and hands were examined. Saliva samples were collected for assessment of filaggrin (FLG) null mutations and an explorative genome-wide association study (GWAS), and levels of various cytokines were assessed from stratum corneum samples. RESULTS: The 2-year and 3-year incidence of HE in the metalwork control group was 20.9% and 32.6%, respectively, which was significantly higher than in the intervention group (odds ratio [OR] 2.63, 95% confidence interval [CI] 1.31 to 5.28, P < .01 and OR 3.47, 95% CI 1.88 to 6.40, P < .0001). The knowledge score was higher in unaffected MWAs (P < .05). Other factors significantly associated with developing HE in MWAs were smoking cigarettes (P < .01) and FLG mutations (P < .001). No significant associations were found regarding epidermal cytokine levels and GWAS. CONCLUSIONS: Health education is effective in primary prevention of HE in MWAs. Individual factors should be considered in targeted counseling.

Economic evaluation of a tertiary prevention program for occupational skin diseases in Germany.

BACKGROUND: Occupational skin diseases (OSDs) are the most common work-related diseases in Germany and responsible for a large individual and financial burden. Therefore, a tertiary individual prevention program (TIP) is offered to patients with severe OSD who are at increased risk of abandoning their profession. OBJECTIVES: To define cost of illness (COI) of OSD in Germany and to economically evaluate the TIP from a societal perspective. METHODS: In this study, data on patients taking part in the TIP (September 2005 to December 2009) were collected. Sociodemographic and medical data, costs, disease severity (Osnabrueck Hand Eczema Severity Index), and quality of life (QoL; Dermatology Life Quality Index) were assessed. COI and cost-effectiveness analyses were performed with a simulated control group. RESULTS: In the analysis, 1041 patients were included. Intervention costs per person were €15 009 with decreasing COI over time. The incremental cost-effectiveness ratio revealed expenses per patient of €8942 for a reduction in severity level and €9093 for an improvement in QoL in the base case. Considering costs for retraining, the break-even point is reached if the TIP prevents retraining in approximately 64% of participants. CONCLUSIONS: The decreased COI in this long-term evaluation indicates that the TIP is cost-effective in patients with severe OSD.

Exposure to solar UV radiation in outdoor construction workers using personal dosimetry.

Occupational exposure to solar UV radiation (SUVR), a Group 1 carcinogen according to the IARC classification is at high exposure levels in outdoor construction workers, usually above the suggested occupational limits. Furthermore, there are no regulations related to this exposure in the EU, except for the artificial UVR. Also, the use of the ICNIRP exposure guideline in an outdoor setting poses problems of adequate dose assessment. In this context, the main purpose of the study was to perform direct measurements of the SUVR dose in outdoor workers from the construction sector, using individual SUVR dosimeters (GENESIS-UV system), for a period of 7 months, from April to October, in a prospective, observational study in two groups of 10 outdoor workers in Romania, located at two different geographic sites. In term of cumulative standard erythema dose (SED), our study population of outdoor construction workers received high levels of solar UV radiation, ranging from 165 SED to 453 SED during 7 months of occupational activity, from April to October. Our results, ranging from 1.28 SED (standard erythema dose) per day to 6.4 SED per day pose an alarm signal to the national and European health authorities to take preventive action for outdoor workers, as the ICNIRP suggested limit value of 1.33 SED for mean daily erythemal UV exposure is vastly exceeded. We suggest that personal dosimetry for SUVR, from simple devices to complex systems as GENESIS-UV should be regularly and mandatory used in outdoor workers, similarly to the usage of personal dosimetry in occupational exposure to ionizing radiations, which could be included in European and national legislation to reduce both, the level of exposure and the detrimental effects on outdoor workers' health.

Tertiary prevention of occupational skin diseases: Prevalence of allergic contact dermatitis and pattern of patch test results.

BACKGROUND: Allergic contact dermatitis (ACD) is one of the most common occupational skin diseases (OSDs). Its prevalence and the causative allergens differ between occupations. OBJECTIVES: To evaluate the prevalence of ACD and the pattern of patch test results of patients taking part in a tertiary individual prevention programme (TIP) for OSD in Germany. PATIENTS AND METHODS: In a retrospective cohort study, the data of 3411 TIP patients patch tested between 2007 and 2016 were analysed. RESULTS: In 2687 (78.8%) patients, work-related skin disease was diagnosed, mostly hand dermatitis. The highest proportion of face dermatitis was seen in painters (8.1%). ACD was most common in painters (56.8%), hairdressers (45.8%), construction workers (31.5%), gardeners/florists (26.7%), and metalworkers (26.5%). On average, hairdressers had the youngest age (31.4 ± 12.6 years, P < 0.0001) and the shortest time in the profession prior to the TIP (mean 13.7 years). The pattern of patch test reactivity showed occupation-specific differences related to work exposures. CONCLUSIONS: Identification of occupational groups at risk for ACD and relevant allergens may help in the development and implementation of targeted prevention strategies. Our data suggest that there should be a particular focus on hairdressers and painters.

Skin Protection Seminars to Prevent Occupational Skin Diseases: Results of a Prospective Longitudinal Study in Apprentices of High-risk Professions.

BACKGROUND: Occupational skin diseases (OSDs) are frequent in professions with exposure to skin hazards. Thus, a health educational intervention for apprentices of high-risk professions was conducted. It was the aim of this study to gain insight into possible effects of this intervention. METHODS: A one-time skin protection seminar was conducted in 140 apprentices of health-related and non-health-related professions [trained cohort (TC)]. In addition, 134 apprentices of the same occupations were monitored [untrained cohort (UTC)]. The OSD-specific knowledge and the skin condition of the hands were assessed at baseline (T0), after the seminar (T1), and after 6 (T2) and 12 months (T3). RESULTS: The OSD-specific knowledge increased in all cohorts from T0 to T3, but we found a significantly higher knowledge in the TC at T2 (p < 0.001, t = 3.6, df = 196, 95% confidence interval = 0.9, 3.3) and T3 (p < 0.001, t = 3.8, df = 196, 95% confidence interval = 1.0, 3.2) compared to the UTC. Our results indicated a better skin condition of the hands in the TC of the health-related professions but not in the non-health-related professions. CONCLUSION: The study indicates that an educational intervention may positively influence the disease-specific knowledge and the prevalence of OSD in apprentices. However, definite conclusions cannot be drawn because of the heterogeneous study cohorts and the study design. Future research should aim at tailoring primary prevention to specific target groups, e.g., in view of the duration and frequency of skin protection education, different professions, and gender-specific prevention approaches.

The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation.

BACKGROUND/PURPOSE: Urocanic acid (UCA) absorbs ultraviolet (UV)B radiation in the epidermis which may interfere with phototherapy. Therefore, the influence of individual levels of UCA on immune reactivity and vitamin D synthesis induced by narrowband UVB radiation was assessed. METHODS: Twenty-eight subjects with irritant contact dermatitis of the hands were irradiated with suberythemal doses of narrowband UVB radiation on their unaffected lower forearms on three consecutive days. Stratum corneum tape strips and epidermal interstitial fluid (ISF) as well as blood samples were analyzed. RESULTS: Narrowband UVB irradiation led to the conversion of trans-UCA into its cis-isomer in the epidermis. The observed increase in 25-hydroxyvitamin D serum concentrations was inversely correlated with the baseline levels of trans-UCA. Furthermore, UVB irradiation induced significant changes in the levels of CXCL10/IP-10, CCL2/MCP-1, CCL4/MIP-1ß, and the IL-1RA/IL-1α ratio. The levels of IL-1α and CXCL9/MIG showed a trend toward increase. The changes in the levels of inflammatory and immunomodulatory mediators did not depend on baseline levels of trans-UCA. CONCLUSION: The results suggest that epidermal levels of trans-UCA affect vitamin D synthesis, but not cutaneous immune reactivity upon repeated exposure to suberythemal doses of narrowband UVB radiation. However, this requires further exploration.

Colonisation with methicillin-resistant Staphylococcus aureus and associated factors among nurses with occupational skin diseases.

OBJECTIVES: To evaluate the prevalence of colonisation with methicillin-resistant Staphylococcus aureus (MRSA), associated factors and the effectiveness of decolonisation procedures among nurses with occupational skin diseases (OSD). METHODS: In a retrospective cohort study, the medical records of 319 nurses from Germany who were screened consecutively for MRSA when participating in a tertiary individual prevention programme (TIP) for severe OSD between July 2009 and December 2014 were evaluated. RESULTS: 90.3% of nurses with severe OSD suffered from hand eczema. 43 were colonised with MRSA on admission (13.5%), mainly in the nose (n=35, 81.4%). However, the hands were affected in more than half of the MRSA carriers (n=24, 55.8%). Risk factors for MRSA colonisation were atopic skin diathesis (OR 2.01, 95% CI 1.03 to 3.92, p=0.049) and presence of atopic dermatitis on other body parts than the hands (OR 4.33, 95% CI 2.23 to 8.43, p<0.001). Hand eczema was significantly more severe in MRSA carriers than in non-carriers (OR 1.23, 95% CI 1.10 to 1.37, p<0.001) and showed a higher prevalence of vesicles, erosions or fissures. MRSA eradication was successful in 67.4% after the first attempt. CONCLUSIONS: Nurses with OSD have a twofold to threefold higher prevalence of MRSA colonisation than what has been reported for point-prevalence screenings among healthcare workers in Germany. Atopic skin diathesis, atopic dermatitis and severe hand eczema are the main risk factors. Thus, prevention and treatment of OSD could be important elements in reduction of colonisation with MRSA among nurses and transmission to others.

Multicentre cohort study 'Rehabilitation of Occupational Skin Diseases - Optimization and Quality Assurance of Inpatient Management (ROQ)': results from a 3-year follow-up.

BACKGROUND: A tertiary individual prevention programme (TIP) is offered to patients with severe occupational skin disease (OSD) in Germany. Previously, it was shown that the burden of OSDs is considerably reduced in patients up to 1 year after the TIP. OBJECTIVES: To evaluate the long-term effects of the TIP. PATIENTS AND METHODS: In a prospective multicentre cohort study, the clinical and patient-reported outcome data 3 years after the TIP were evaluated. RESULTS: Of the 1788 patients initially included in the study, 1410 were available for the 3-year follow-up analysis. The severity of OSD, the use of topical corticosteroids and days of absence from work were significantly reduced 3 years after the TIP, and the quality of life and skin protective behaviour were significantly improved. Of the patients, 96.9% were able to resume work. One thousand one hundred and sixty-six patients (82.7%) were still working 3 years after the TIP, 874 of them (75.0%) in the same occupational field. Hairdressers had the lowest rate of remaining in their original profession (41.3%). CONCLUSIONS: The follow-up during 3 years of this unique cohort of patients with OSDs shows that the TIP is associated with sustained improvements in terms of disease severity, ability to work, quality of life, and prognosis.

Prevalence of foot eczema and associated occupational and non-occupational factors in patients with hand eczema.

BACKGROUND: Foot eczema often occurs in combination with hand eczema. However, in contrast to the situation with hand eczema, knowledge about foot eczema is scarce, especially in occupational settings. OBJECTIVE: To evaluate the prevalence of foot eczema and associated factors in patients with hand eczema taking part in a tertiary individual prevention programme for occupational skin diseases. PATIENTS/MATERIALS/METHODS: In a retrospective cohort study, the medical records of 843 patients taking part in the tertiary individual prevention programme were evaluated. RESULTS: Seven hundred and twenty-three patients (85.8%) suffered from hand eczema. Among these, 201 patients (27.8%) had concomitant foot eczema, mainly atopic foot eczema (60.4%). An occupational irritant component was possible in 38 patients with foot eczema (18.9%). In the majority of patients, the same morphological features were found on the hands and feet (71.1%). The presence of foot eczema was significantly associated with male sex [odds ratio (OR) 1.78, 95% confidence interval (CI) 1.29-2.49], atopic hand eczema (OR 1.60, 95%CI: 1.15-2.22), hyperhidrosis (OR 1.73, 95%CI: 1.33-2.43), and the wearing of safety shoes/boots at work (OR 2.04, 95%CI: 1.46-2.87). Tobacco smoking was associated with foot eczema (OR 1.79, 95%CI: 1.25-2.57), in particular with the vesicular subtype. CONCLUSIONS: Foot eczema is common in patients with hand eczema, and is related to both occupational and non-occupational factors.

Development of a regulatable oncolytic herpes simplex virus type 1 recombinant virus for tumor therapy.

Oncolytic viruses are genetically modified viruses that preferentially replicate in host cancer cells, leading to the production of new viruses and, ultimately, cell death. Currently, no oncolytic viruses that are able to kill only tumor cells while leaving normal cells intact are available. Using T-REx (Invitrogen, Carlsbad, CA) gene switch technology and a self-cleaving ribozyme, we have constructed a novel oncolytic HSV-1 recombinant, KTR27, whose replication can be tightly controlled and regulated by tetracycline in a dose-dependent manner. Infection of normal replicating cells as well as multiple human cancer cell types with KTR27 in the presence of tetracycline led to 1,000- to 250,000-fold-higher progeny virus production than in the absence of tetracycline, while little viral replication and virus-associated cytotoxicity was observed in infected growth-arrested normal human cells. We show that intratumoral inoculation with KTR27 markedly inhibits tumor growth in a xenograft model of human non-small-cell lung cancer in nude mice. It is shown further that replication of KTR27 in the inoculated tumors can be efficiently controlled by local codelivery of tetracycline to the target tumors at the time of KTR27 inoculation. Collectively, KTR27 possesses a unique pharmacological feature that can limit its replication to the targeted tumor microenvironment with localized tetracycline delivery, thus minimizing unwanted viral replication in distant tissues following local virotherapy. This regulatory mechanism would also allow the replication of the virus to be quickly shut down should adverse effects be detected.

Pilot study: optical coherence tomography as a non-invasive diagnostic perspective for real time visualisation of onychomycosis.

The objective of this study was to compare optical coherence tomography (OCT) with conventional techniques such as KOH-preparation, culture and histology in the identification of the fungal elements in the nail. A total of 18 patients were examined; 10 with clinically evident onychomycosis in toe nails, two with psoriatic nail lesions, one with nail affection caused by lichen planus and five healthy controls. Serial in vivo OCT analyses of onychomycosis was performed prior to KOH-preparation, culture and punch biopsy of the nail plate for consecutive histology. Fungal elements were detected non-invasively in vivo using OCT in all 10 patients with histologically proven onychomycosis. Fungal elements were detectable as highly scattering elongated structures inside the nail plate, in the middle of the areas of homogeneous decrease in signal intensity. KOH-preparations and culture did reveal a positive result in 5/6 out of 10 patients. In patients with psoriasis, lichen planus as well as in the healthy controls, no fungal infection could be detected by either method used. OCT is a reliable, easy to use, non-invasive and non-destructive method to visualise fungal elements in vivo in onychomycosis, even in cases of false negative KOH-preparation and culture. Furthermore, OCT offers the opportunity to screen several areas of the same nail plate and to detect fungal elements during local or systemic therapy.

Prevention of genital herpes simplex virus type 1 and 2 disease in mice immunized with a gD-expressing dominant-negative recombinant HSV-1.

CJ9-gD is a novel herpes simplex virus (HSV) type 1 recombinant virus that is completely replication-defective, expresses high-levels of HSV-1 major antigen glycoprotein D (gD), and can function in trans to inhibit replication of wild-type HSV-1 and HSV-2 in co-infected cells. Here, we show that immunization with CJ9-gD elicits strong and long-lasting humoral and Th1-like cellular immune responses against both HSV-1 and HSV-2. Mice immunized with CJ9-gD exhibited significant reductions in the extent and duration of intravaginal replication of challenge HSV-1 and HSV-2 compared with mock-immunized controls, and were completely protected from local or systemic herpetic disease after intravaginal challenge with wild-type HSV-1 or HSV-2.

High-level expression of glycoprotein D by a dominant-negative HSV-1 virus augments its efficacy as a vaccine against HSV-1 infection.

Using the T-REx (Invitrogen, Carlsbad, CA) gene switch technology, we previously generated a dominant-negative herpes simplex virus (HSV)-1 recombinant, CJ83193, capable of inhibiting its own replication as well as that of wild-type HSV-1 and HSV-2. It has been further demonstrated that CJ83193 is an effective vaccine against HSV-1 infection in a mouse ocular model. To ensure its safety and augment its efficacy, we generated an improved CJ83193-like HSV-1 recombinant, CJ9-gD, which contains a deletion in an HSV-1 essential gene and encodes an extra copy of gene-encoding glycoprotein D (gD) driven by the tetO-bearing human cytomegalovirus major immediate-early promoter. Unlike CJ83193, which exhibits limited plaque-forming capability in Vero cells and expresses little gD in infected cells, CJ9-gD is completely replication defective, yields high-level expression of gD following infection, and cannot establish detectable infection in mouse trigeminal ganglia following intranasal and ocular inoculation. Mice immunized with CJ9-gD produced 3.5-fold higher HSV-1 neutralizing antibody titer than CJ83193-immunized mice, and were completely protected from herpetic ocular disease following corneal challenge with wild-type HSV-1. Moreover, immunization of mice with CJ9-gD elicited a strong HSV-1-specific T-cell response and led to an 80% reduction in latent infection by challenge wild-type HSV-1 compared with the mock-immunized control.

Immunization with a dominant-negative recombinant HSV type 1 protects against HSV-1 skin disease in guinea pigs.

CJ9-gD belongs to a new class of replication-defective recombinant herpes simplex viruses (HSVs) type 1 that can function in trans to prevent the replication of wild-type HSV in co-infected cells. Furthermore, CJ9-gD cannot establish latent infection in vivo and it expresses high levels of the major HSV-1 antigen glycoprotein D immediately following infection. In this study we show that guinea pigs immunized with CJ9-gD developed at least 9,600-fold higher titers of HSV-1-specific neutralization antibodies than mock-immunized controls. After challenge with wild-type HSV-1, all 10 mock-immunized guinea pigs developed multiple skin lesions with an average of 53.3 lesions per animal, whereas only 2 minor lesions were found in 1 of 10 CJ9-gD-immunized animals, representing a 267-fold reduction on the incidence of primary herpetic skin lesions in immunized animals. Quantitative PCR analysis revealed that the amount and frequency of wild-type HSV-1 viral DNA present in dorsal root ganglia of immunized animals was significantly lower than that in mock-immunized controls. Collectively, we demonstrate that vaccination with CJ9-gD elicits strong and protective immune responses against primary HSV-1 skin disease and reduces the extent of latent infection by challenge virus.