title: From genome-wide arrays to tailor-made biomarker readout - Progress towards routine analysis of skin sensitizing chemicals with GARD.
abstract: Allergic contact dermatitis (ACD) initiated by chemical sensitizers is an important public health concern. To prevent ACD, it is important to identify chemical allergens to limit the use of such compounds in various products. EU legislations, as well as increased mechanistic knowledge of skin sensitization have promoted development of non-animal based approaches for hazard classification of chemicals. GARD is an in vitro testing strategy based on measurements of a genomic biomarker signature. However, current GARD protocols are optimized for identification of predictive biomarker signatures, and not suitable for standardized screening. This study describes improvements to GARD to progress from biomarker discovery into a reliable and cost-effective assay for routine testing. Gene expression measurements were transferred to NanoString nCounter platform, normalization strategy was adjusted to fit serial arrival of testing substances, and a novel strategy to correct batch variations was presented. When challenging GARD with 29 compounds, sensitivity, specificity and accuracy could be estimated to 94%, 83% and 90%, respectively. In conclusion, we present a GARD workflow with improved sample capacity, retained predictive performance, and in a format adapted to standardized screening. We propose that GARD is ready to be considered as part of an integrated testing strategy for skin sensitization.
authors.affiliation: Department of Immunotechnology, Medicon Village (406), 22381 Lund, Sweden. Electronic address: andy.forreryd@immun.lth.se.
authors.forename: Andy
authors.initials: A
authors.lastname: Forreryd
authors.affiliation: Department of Immunotechnology, Medicon Village (406), 22381 Lund, Sweden. Electronic address: kathrin.zeller@immun.lth.se.
authors.forename: Kathrin S
authors.initials: KS
authors.lastname: Zeller
authors.affiliation: Department of Immunotechnology, Medicon Village (406), 22381 Lund, Sweden. Electronic address: tim.lindberg@immun.lth.se.
authors.forename: Tim
authors.initials: T
authors.lastname: Lindberg
authors.affiliation: SenzaGen AB, Medicon Village (406), 22381 Lund, Sweden. Electronic address: henrik.johanson@senzagen.com.
authors.forename: Henrik
authors.initials: H
authors.lastname: Johansson
authors.affiliation: Department of Immunotechnology, Medicon Village (406), 22381 Lund, Sweden. Electronic address: malin.lindstedt@immun.lth.se.
authors.forename: Malin
authors.initials: M
authors.lastname: Lindstedt
mesh_terms: D000485:Allergens / Q000633:toxicity*; D000826:Animal Testing Alternatives; D015415:Biomarkers / Q000032:analysis; D045744:Cell Line, Tumor; D017449:Dermatitis, Allergic Contact / Q000235:genetics*; D020869:Gene Expression Profiling; D015894:Genome, Human; D006241:Haptens / Q000633:toxicity*; D006801:Humans; D060388:Support Vector Machine
chemical_list: D000485:Allergens; D015415:Biomarkers; D006241:Haptens
keywords: GARD; In vitro assay; Predictive genomic biomarker signature; Skin sensitization