European Surveillance System on Contact Allergies (ESSCA): Characteristics of patients patch tested and diagnosed with irritant contact dermatitis

The BMDC model, a performant cell-based test to assess the sensitizing potential and potency of chemicals including pre/pro-haptens

BACKGROUND

Chemical-induced allergies at workplace represent a significant occupational health issue. These substances must be properly identified as sensitizers. In previous studies, an original model using mouse bone marrow-derived dendritic cells (BMDC) was developed for this purpose.

OBJECTIVES

The aim of this study was to evaluate the predictive capacity of the BMDC model with a large panel of sensitizers (including pre- and pro-haptens) and non-sensitizers.

METHODS

The readout from the BMDC model is based on expression levels of six phenotypic markers measured by flow cytometry.

RESULTS

The results indicate that 29 of the 37 non-sensitizers, and 81 of the 86 sensitizers were correctly classified compared to the Local Lymph Node Assay (LLNA). Statistical analysis revealed the BMDC model to have a sensitivity of 94%, a specificity of 78%, and an accuracy of 89%. The EC2 (Effective Concentration) values calculated with this model allow sensitizers to be categorized into four classes: extreme, strong, moderate and weak.

CONCLUSIONS

These excellent predictive performances show that the BMDC model discriminates between sensitizers and non-sensitizers with outstanding precision equal to or better than existing validated alternative models. Moreover, this model allows to predict sensitization potency of chemicals. The BMDC test could therefore be proposed as an additional tool to assess the sensitizing potential and potency of chemicals.

Occupational Hand Dermatitis

PURPOSE OF REVIEW

Occupational hand dermatitis is a common work-related disorder of the skin. Prevention and management of this disease is critical to improving workers' quality of life and for occupation-specific retention.

RECENT FINDINGS

This is a critical review of the current literature on occupational hand dermatitis. Occupational dermatitis continues to have a high prevalence among workers although the overall incidence may be slowly decreasing. Irritant contact dermatitis due to wet work exposure is the most common cause of occupational hand dermatitis. Healthcare workers, hairdressers, and metal workers are at particularly high risk for this disease. While some prevention programs have been ineffective in mitigating occupational hand dermatitis, other more resource-intensive initiatives may have benefit. Continued research is needed on ways to manage wet work exposures and on scalable, effective prevention programs for occupational hand dermatitis. The spectrum of culprit contact allergens continues to evolve, and vigilance for potential occupation-specific allergens remains important.

Exposure and work-related factors in subjects with hand eczema: data from a cross-sectional questionnaire within the Lifelines Cohort study

BACKGROUND

Hand eczema (HE) is the most frequent occupational skin disease. However, studies on non-occupational wet exposure, occupations not considered as high-risk, and socioeconomic factors are scarce.

OBJECTIVES

To investigate the association between HE and occupational and non-occupational wet exposure and work-related factors in the Dutch general population.

METHODS

Within the Lifelines Cohort Study, participants with HE were identified by a digital add-on questionnaire, including questions regarding exposure. Data on work-related and socioeconomic factors were collected from baseline.

RESULTS

Overall, 57 046 participants (42.0%) were included. Occupational and non-occupational wet exposure were positive associated with HE in the past year (Odds Ratios (OR) 1.35 95% confidence interval (CI) [1.22-1.49] and OR 1.34 95% CI [1.17-1.53], respectively). Positive associations for high-risk occupations (OR 1.20 95% CI [1.06-1.36] for personal care workers in health services and OR 1.25 95% CI [1.06-1.48] for nursing and midwifery professionals), occupations not considered as high-risk (OR 1.19 95% CI [1.03-1.39 for legal, social and religious associate professionals) and higher levels of education were found (OR 1.17 95% CI [1.04-1.32] and OR 1.18 95% CI [1.04-1.34] for middle and high level, respectively).

CONCLUSION

Preventive strategies for HE should focus on avoidance of all exposure to wet, regardless of origin. In addition, job tasks instead of job title should be taken into account. As previous results on the association between HE and socioeconomic factors differ, future research should focus on a uniform definition. This article is protected by copyright. All rights reserved.

In Vitro Monitoring of Human T Cell Responses to Skin Sensitizing Chemicals-A Systematic Review

Background: Chemical allergies are T cell-mediated diseases that often manifest in the skin as allergic contact dermatitis (ACD). To prevent ACD on a public health scale and avoid elicitation reactions at the individual patient level, predictive and diagnostic tests, respectively, are indispensable. Currently, there is no validated in vitro T cell assay available. The main bottlenecks concern the inefficient generation of T cell epitopes and the detection of rare antigen-specific T cells. Methods: Here, we systematically review original experimental research papers describing T cell activation to chemical skin sensitizers. We focus our search on studies published in the PubMed and Scopus databases on non-metallic allergens in the last 20 years. Results: We identified 37 papers, among them 32 (86%) describing antigen-specific human T cell activation to 31 different chemical allergens. The remaining studies measured the general effects of chemical allergens on T cell function (five studies, 14%). Most antigen-specific studies used peripheral blood mononuclear cells (PBMC) as antigen-presenting cells (APC, 75%) and interrogated the blood T cell pool (91%). Depending on the individual chemical properties, T cell epitopes were generated either by direct administration into the culture medium (72%), separate modification of autologous APC (29%) or by use of hapten-modified model proteins (13%). Read-outs were mainly based on proliferation (91%), often combined with cytokine secretion (53%). The analysis of T cell clones offers additional opportunities to elucidate the mechanisms of epitope formation and cross-reactivity (13%). The best researched allergen was p-phenylenediamine (PPD, 12 studies, 38%). For this and some other allergens, stronger immune responses were observed in some allergic patients (15/31 chemicals, 48%), illustrating the in vivo relevance of the identified T cells while detection limits remain challenging in many cases. Interpretation: Our results illustrate current hardships and possible solutions to monitoring T cell responses to individual chemical skin sensitizers. The provided data can guide the further development of T cell assays to unfold their full predictive and diagnostic potential, including cross-reactivity assessments.