Alternative skin sensitization prediction and risk assessment using proinflammatory biomarkers, interleukin-1 beta (IL-1ß) and inducible nitric oxide synthase (iNOS).

As an alternative to animal tests for skin sensitization potency and risk assessment, cell viability and biomarkers related to skin sensitization were analyzed in THP-1 human monocytic leukemia cells. Cell viabilities of 90% (CV90) and 75% (CV75) were determined for 24 selected test chemicals. Further biomarkers related to skin sensitization were also determined under equivalent comparative conditions. In cell viability analyses, potent skin sensitizers exhibited high cytotoxicity, but non-sensitizers did not display this tendency. In biomarker analyses, interleukin-I beta (IL-1ß), inducible nitric oxide synthase (iNOS), IL-1ß+iNOS, and THP-1 IL-1ß+Raw 264.7 IL-1ß were found to be suitable for prediction of skin sensitization potency following classification as either skin sensitizers or non-sensitizers (accuracies of 91.7%, 87.5%, 83.3%, and 82.6%, respectively). A significant positive correlation was found between biomarkers and skin sensitization potency, with a correlation coefficient (R) of 0.7 or more (correlation coefficients of 0.77, 0.72, 0.7, and 0.84, respectively). Finally, the skin sensitization potency effective threefold concentration (EC) 3% was predicted using a biomarker equation, with resulting prediction rates (match rate with actual data) of 58.3%, 54.2%, 62.5%, and 60.9%, respectively. The prediction accuracy for the EC3 value obtained from animal data was calculated as 83.3%, 79.2%, 79.2%, and 73.9%, respectively. Thus, these biomarkers, IL-1ß and iNOS, may be alternatively used to predict skin sensitization potency and risk assessment.

Retrospective review of insurance coverage for patch testing.

BACKGROUND: There is a paucity of data on the burden of insurance limitations for patients undergoing patch testing. OBJECTIVE: To characterize the burden of insurance limitations and its impact on differences in management and execution of patch testing. METHODS: A retrospective chart review was performed on patients with a diagnosis of contact dermatitis (International Classification of Disease [ICD], Ninth Edition, code ICD 692) who received patch testing (Current Procedural Terminology code 95044) at the George Washington Medical Faculty Associates Dermatology Clinic between January 1, 2015 and June 30, 2017. Variables including allergen limitations were compared between government-sponsored insurance and private insurance providers (eg, Insurers A, B, C, and D). RESULTS: A total of 371 records were identified. Government-sponsored insurance patients encountered allergen limitations more frequently than private insurance patients (86.8% vs 14.2%, P < .0001). Insurer C and D patients were least likely to encounter allergen limitations (1.2% vs 0%, P < .0001) and were tested to the most allergens (mean = 146 vs 152, P < .0001). Insurer A patients had the least allergens tested among those privately insured. CONCLUSION: Considering modification of insurance policies to allow patch testing with a larger number of allergens without restrictions is needed, with the goal of improving quality of life of these patients while saving costs from chronic use of topical corticosteroids.

IL-1α and IL-1ß as alternative biomarkers for risk assessment and the prediction of skin sensitization potency.

Potential biomarkers of skin sensitization in RAW264.7 mouse macrophages were investigated as alternatives to animal experiments and risk assessment. The concentrations that resulted in a cell viability of 90% (CV90) and 75% (CV75) were calculated by using a water-soluble tetrazolium salt (WST)-1 assay and used to analyze the skin sensitization potency of 23 experimental materials under equivalent treatment conditions. In addition, the expression of interleukin (IL)-1α, IL-1ß, IL-31, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), and cyclooxygenase-2 (COX-2) was analyzed utilizing Western blotting. In the cell viability analysis, skin sensitizers were generally more cytotoxic and exhibited increased skin sensitization potency. However, nonsensitizers did not show any marked cytotoxic tendency. Biomarker analysis demonstrated that IL-1α, IL-1ß, and the combination of IL-1α and IL-1ß (IL-1α + IL-1ß) predicted reliably skin sensitization potential (1) sensitivities of 94.4%, 83.3%, and 83.3%, specificities of 100%, 100%, and 100%, and (2) accuracies of 95.7%, 87%, and 87%, respectively. These observations correlated most reliably as indicators for skin sensitization potency. Data suggest that IL-1α and IL-1ß may serve as potential biomarkers for skin sensitization and provide an alternative method to animal experiments for prediction of skin sensitization potency and risk assessment.

The Role of the Skin Barrier in Occupational Skin Diseases.

Occupational skin diseases (OSDs) are the second most common occupational diseases worldwide. Occupational contact dermatitis (OCD) is the most frequent OSD, and comprises irritant contact dermatitis (ICD), allergic contact dermatitis (ACD), contact urticaria and protein contact dermatitis. There are many endogenous and exogenous factors which affect the development of OCD, including age, sex, ethnicity, atopic skin diathesis, certain occupations and environmental factors. One of the most important contributing causes is skin barrier dysfunction. The skin provides a first-line defense from environmental assaults and incorporates physical, chemical and biological protection. Skin barrier disturbance plays a crucial role in various skin diseases such as atopic dermatitis (AD), ichthyosis, ICD and ACD. Genetic factors, such as filaggrin gene (FLG) mutations, and external factors, such as skin irritants interfering with stratum corneum structure and composition, may lead to abnormalities in skin barrier function and increased vulnerability to skin diseases. FLG encodes the cornified envelope protein, filaggrin, which is involved in skin barrier function. FLG mutation is associated with the development of OCD. High-risk occupations for OCD include health care workers, hairdressers and construction workers. There are often multiple contributing causes to OCD, as workers are exposed to both irritants and allergens. AD is also associated with skin barrier disruption and plays an important role in OCD. ICD often precedes and facilitates the development of ACD, with impairment of the skin barrier contributing to the concurrence of ICD and ACD in many workers with OCD.

Investigation of the skin sensitizing properties of 5 osmolytic prodrugs in a weight-of-evidence assessment, employing in silico, in vivo, and read across analyses.

The amino acid esters ethyl glycinate (EG), DL-α-tocopheryl-(mono-)betainate hydrochloride (TMB), DL-α-tocopheryl-(mono-)glycinate hydrochloride (TMG), DL-α-tocopheryl-(mono-)prolinate hydrochloride (TMP), and DL-α-tocopheryl-(mono-)sarcosinate hydrochloride (TMS) were previously shown to exert an osmoprotective function to human skin in vitro. Based on literature data, the parent compounds α-tocopherol (vitamin E) and the amino acids glycine, betaine (trimethylated glycine), proline, and sarcosine (N-methylated glycine) are not considered to be sensitizers. To investigate skin sensitizing properties of the esters, EG, TMG, and TMP were tested in the Local Lymph Node Assay (LLNA). Remaining esters were assessed by read across analysis considering structural similarities and mechanistic aspects. The LLNA results were consistent with in silico outcomes from ToxTree 2.5.0 indicative for protein binding; EG was negative; TMG and TMP were positive. Since TMB and TMS showed structural similarities to TMG and TMP and were also positive in ToxTree, it was concluded that both TMB and TMS can also be expected to have a skin sensitizing potential and therefore animal testing was waived.

Skin irritation and sensitization: mechanisms and new approaches for risk assessment. 1. Skin irritation.

Cutaneous irritation presents a major health problem with serious social and occupational impact. The interaction between an irritant and the human skin depends on multiple factors: the intrinsic properties and the nature of the irritant itself, and specific individual- and environment-related variables. The main pathological mechanisms of irritancy include skin barrier disruption, induction of a cytokine cascade and involvement of the oxidative stress network; all of them resulting in a visible or subclinical inflammatory reaction. In vivo, different non-invasive parameters for the evaluation of skin irritation and irritant potential of compounds and their specific formulations have been introduced, such as epidermal barrier function, skin hydration, surface pH, lipid composition, skin colour and skin blood flow. The diverse physiological changes caused by irritating agents require implementation of a multiparametric approach in the evaluation of cutaneous irritancy.

Skin capacitance imaging and corneosurfametry. A comparative assessment of the impact of surfactants on stratum corneum.

Silicon image sensor (SIS) technology was recently introduced as an innovative tool (SkinChip, L'Oréal) providing sensitive imaging of the skin capacitance. This method can detect discrete focal variations in skin surface hydration, and thus early discrete manifestations of skin irritation induced by surfactants. In the present in vivo study, 2 neat and diluted shampoos, and 5% and 10% sodium laurylsulfate solutions were tested on human skin. Each surfactant solution was gently rubbed on the skin using wet hair wicks mimicking the casual use of a shampoo on the scalp. Clinical and SIS evaluations were carried out. In addition, the same products were tested using the ex vivo corneosurfametry bioassay performed on human stratum corneum (SC) harvested by cyanoacrylate skin surface strippings. The colourimetric index of mildness (CIM) was measured on these samples. The product reactivity with the SC was recognized by darker skin capacitance images, and by both lowered SkinChip-generated values and lowered CIM values. The extent in changes varied according to the nature of the test products and their concentrations. The SkinChip image changes likely corresponded to the acute surfactant-induced water swelling of the corneocytes. Skin capacitance imaging and corneosurfametry allow to disclose discrete surfactant-induced alterations of corneocytes.

Proposal for a risk assessment methodology for skin sensitization based on sensitization potency data.

In this paper, we propose a quantitative risk assessment methodology for skin sensitization aiming at the derivation of 'safe' exposure levels for sensitizing chemicals, used e.g., as ingredients in consumer products. Given the limited number of sensitizers tested in human sensitization tests, such as the human repeat-insult patch test (HRIPT) or the human maximization test (HMT), we used EC3 values from the local lymph node assay (LLNA) in mice because they provide the best quantitative measure of the skin sensitizing potency of a chemical. A comparison of LLNA EC3 values with HRIPT and HMT LOEL, and NOEL values was carried out and revealed that the EC3, expressed as area dose, can be used as a surrogate value for the human NOEL in risk assessment. The uncertainty/extrapolation factor approach was used to derive (a) an 'acceptable non-sensitizing area dose' (ANSAD) to protect non-allergic individuals against skin sensitization and (b) an 'acceptable non-eliciting area dose' (ANEAD) to protect allergic individuals against elicitation of allergic contact dermatitis. For ANSAD derivation, interspecies, intraspecies and time extrapolation factors are applied to the LLNA EC3. For ANEAD derivation, additional application of a variable sensitization-elicitation extrapolation factor is proposed. Values for extrapolation factors are derived and discussed, the proposed methodology is applied to the sensitizers methylchloroisothiazolinone/methylisothiazolinone, cinnamic aldehyde and nickel and results are compared to published risk assessments.

Clinical and occupational outcomes in health care workers with natural rubber latex allergy.

BACKGROUND: There is limited information pertaining to clinical outcomes and economic consequences of natural rubber latex (NRL) allergy in health care workers (HCWs). OBJECTIVE: To evaluate retrospectively health and economic outcomes in HCWs identified with NRL allergy and percutaneous reactivity to NRL. METHODS: Sixty-seven HCWs with NRL allergy, confirmed by percutaneous reactivity to non-ammoniated latex (NAL) extract, were administered a detailed questionnaire to evaluate clinical and economic outcomes of active work and environmental interventions subsequent to recognition of work-related symptoms associated with NRL gloves. RESULTS: Diagnoses based on predetermined case definitions associated with direct or indirect exposure to NRL gloves included contact urticaria in 67 (100%); work-related rhinitis in 23; work-related asthma symptoms in 25; and work-related anaphylaxis in 4 workers. Work related symptoms reportedly resolved in 44 of 49 (90%) of NAL skin test-positive workers who had reported skin, respiratory, and/or systematic symptoms and remained in their current work area and who switched to non-NRL gloves. Four of 24 (17%) workers with work-related asthma symptoms were compelled to change employment to NRL-safe workplaces, resulting in a mean 24% reduction in annual income. CONCLUSIONS: Clinical outcomes in this group of HCWs with NRL allergy were favorable after institution of interventions but incurred deleterious consequences in a minority of workers.

Assessment of balsam of Peru patch tests.

To find an ideal test technique for as low a dose of balsam of Peru (Myroxylon Pereirae) as possible, subjects testing positive to balsam of Peru are re-tested with a 25% concentration of balsam of Peru in petrolatum. Applications are with Finn Chambers for 6 different application times, and directly by foils for 96 h (4 days (D)). The goals are to confirm which subjects are positive and which are not, and, using that information, to see if it is possible to distinguish between these 2 groups, tested concomitantly at much lower serial dose levels, in terms of perfusion or by visual assessments. 5 different serial doses are applied with strips for 3-96 h (4D) and with foils for 96 h (4D). The Finn Chamber tests allow a distinction between visually positive and negative subjects supported by perfusion assessments. With the foils, a 24x lower serial dose level than with the 25% test substance is sufficient to distinguish between positive and negative subjects in terms of perfusion values. This approach requires readings up to 9 days. With this test, the visual approach yields only 3 of 10 positive subjects. This study demonstrates that a lower test dose is possible with perfusion assessments compared to visual ones.

Allergic contact dermatitis from azathioprine.

A 51-year-old production mechanic for a pharmaceutical company complained of a dermatitis involving his hands. The onset of the eruption coincided with when he was placed on the production packing line for azathioprine tablets. Patch testing showed a positive allergic reaction only to azathioprine diluted in petrolatum. A pharmaceutical product such as azathioprine may need to be considered as a cause for allergic contact dermatitis in patients with a history of exposure during the manufacturing process.

Outcome of job change in patients with occupational chromate dermatitis.

Patients with allergic contact dermatitis due to dichromate are reputed to have a bad prognosis. Based on the Swiss Law on Accidents Insurance, the Swiss National Accidents Insurance Organization (SNAIO) may issue a declaration of medical inability (DMI) in cases of severe occupational dichromate dermatitis. With such a DMI, an employee is not allowed to perform any further work in contact with dichromate or cement. In this study, we reviewed medical records from 88 construction workers with DMI due to occupational dichromate dermatitis, between 1986 and 1989. Follow-up was performed by standardized questionnaire. 63 patients (72%) healed in the first few years after DMI. These patients mostly changed industry and strictly avoided all contact with cement or chromium salts. A few retired early. The outcome of our study is favorable in comparison to studies from other countries without the DMI mechanism. We conclude that strict allergen avoidance enforced by authorities, and financial support in the case of job change, are important factors in improving the prognosis in occupational dichromate dermatitis.