Gene expression based molecular test as diagnostic aid for the differential diagnosis of psoriasis and eczema in formalin fixed and paraffin embedded tissue, microbiopsies and tape strips

A Review of Hand Eczema Subtypes: Clinical Features, Biomarkers and Treatment Strategies

Hand eczema is a common dermatological condition that significantly impairs quality of life. The classification of hand eczema has been considered an essential step for its management. The diagnosis of hand eczema relies on the aetiological and clinical features of hand lesions, a process complicated by the heterogeneous presentations and the considerable overlap among its subtypes. However, the investigation of hand eczema biomarkers and the advent of targeted therapies have shed light on the underlying pathogenic mechanisms. This review adopts a subtype-specific approach to hand eczema, addressing clinical, pathogenic and therapeutic factors, with the aim of providing a comprehensive understanding of this heterogeneous condition from the perspective of its subtypes.

Tape-strip profiling identifies unique immune and lipid dysregulation in patients with seborrheic dermatitis

BACKGROUND

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin disease with limited understanding of its pathophysiology. Molecular profiling has been limited by invasiveness of sampling methods.

OBJECTIVE

To analyze the molecular skin profile of adult patients with SD using tape strips.

METHODS

Tape-strips obtained from facial lesions of 26 adult SD patients and 18 demographically matched healthy controls were evaluated with RNA sequencing.

RESULTS

SD molecular skin fingerprint was characterized by strong and significant upregulation of interleukin (IL)23/T-helper (Th)17 and Th22 (i.e. IL23A, IL22, PI3, LL37, S100A8, S100A12), some Th1 skewing (OASL, STAT1, CXCL9), and limited Th2 modulation. A parallel downregulation of barrier markers (CLDN1/8, FA2H, ELOVL3) was also observed.

LIMITATIONS

Limited representation of mild and severe SD patients.

CONCLUSION

These data deepen our understanding of SD suggesting that it has robust Th17/Th22, some Th1 skewing, and minimal Th2 activation, and associated skin barrier alterations. This provides rationale for novel immunomodulatory treatment approaches for SD patients targeting IL23/Th17 and/or Th22 pathways.

Beyond the dichotomy: understanding the overlap between atopic dermatitis and psoriasis

Atopic dermatitis and psoriasis have traditionally been considered distinct inflammatory skin diseases with unique pathogenic mechanisms. However, accumulating evidence suggests significant overlap in their immunological pathways, metabolic features, and microbiome characteristics, challenging this conventional dichotomy. This review comprehensively examines the complex relationship between psoriasis and atopic dermatitis, with particular emphasis on their shared and distinct pathogenic mechanisms. We analyze the immunological networks, metabolic pathways, and microbial factors contributing to their development and progression. The review expands upon the disease spectrum hypothesis and discusses the nomenclature for conditions exhibiting features of both diseases. We critically evaluate the clinical and histopathological characteristics of concomitant psoriasis and atopic dermatitis, highlighting recent advances in molecular diagnostics for accurate disease differentiation. Importantly, we propose standardized diagnostic criteria for psoriasis dermatitis and examine current therapeutic strategies for managing overlapping conditions. Recent developments in targeted therapies and their implications for treatment selection are thoroughly discussed. By synthesizing current evidence and identifying knowledge gaps, this review provides insights into the complex interplay between psoriasis and atopic dermatitis, aiming to guide clinical decision-making and future research directions in this evolving field.

Psoriasis: The Versatility of Mesenchymal Stem Cell and Exosome Therapies

Mesenchymal stem cells (MSCs) are multilineage differentiating stromal cells with extensive immunomodulatory and anti-inflammatory properties. MSC-based therapy is widely used in the treatment of various pathologies, including bone and cartilage diseases, cardiac ischemia, diabetes, and neurological disorders. Along with MSCs, it is promising to study the therapeutic properties of exosomes derived from MSCs (MSC-Exo). A number of studies report that the therapeutic properties of MSC-Exo are superior to those of MSCs. In particular, MSC-Exo are used for tissue regeneration in various diseases, such as healing of skin wounds, cancer, coronary heart disease, lung injury, liver fibrosis, and neurological, autoimmune, and inflammatory diseases. In this regard, it is not surprising that the scientific community is interested in studying the therapeutic properties of MSCs and MSC-Exo in the treatment of psoriasis. This review summarizes the recent advancements from preclinical and clinical studies of MSCs and MSC-Exo in the treatment of psoriasis, and it also discusses their mechanisms of therapeutic action involved in the treatment of this disease.

Non-invasive epidermal proteome assessment-based diagnosis and molecular subclassification of psoriasis and eczematous dermatitis

Background

Immunologic heterogeneity is known to exist within both eczematous dermatitis and psoriasis; however, selection of molecularly targeted therapies for individual patients generally does assess for or incorporate such information about patient-specific immune changes.

Objective

We sought to develop a rapid, non-invasive method for obtaining and analyzing epidermal protein biomarkers from skin and utilize this methodology to dissect immunologic heterogeneity in both psoriasis and eczematous dermatitis.

Methods

We optimize and evaluate detergent-based immune profiling system (DIPS) which utilizes a combination of two detergents to solubilize full-thickness epidermis when applied to the skin with an applicator. Downstream proteomic profiling of this material allows high-throughput immunologic characterization of immune biomarkers.

Results

DIPS was performed on 43 patients with psoriasis and 27 patients with eczematous dermatitis. This approach was found to be painless, nonscarring, and enabled rapid turnaround from sample collection to data output. We used this approach to accurately differentiate psoriasis and eczema using a limited set of proteins and to identify cases of eczema/psoriasis overlap with non-canonical molecular profiles. Additionally, we measured patient-specific cytokine profiles in eczema that correlated with response to IL-4Rα blockade.

Conclusion

DIPS is a promising new non-invasive cutaneous immune profiling approach that can deconvolute immune heterogeneity amongst patients with both psoriasis and eczematous dermatitis.

Clinical Implication

DIPS has potential applications in both research and day-to-day dermatologic practice and may help personalize diagnosis and medication selection in patients with inflammatory skin diseases.

Capsule summary

Detergent-based immune profiling system (DIPS), a novel non-invasive approach for molecular evaluation of skin disease, is described and evaluated in psoriasis and eczematous dermatitis.

Integrating multi-omics approaches in deciphering atopic dermatitis pathogenesis and future therapeutic directions

Atopic dermatitis (AD), a complex and heterogeneous chronic inflammatory skin disorder, manifests in a spectrum of clinical subtypes. The application of genomics has elucidated the role of genetic variations in predisposing individuals to AD. Transcriptomics, analyzing gene expression alterations, sheds light on the molecular underpinnings of AD. Proteomics explores the involvement of proteins in AD pathophysiology, while epigenomics examines the impact of environmental factors on gene expression. Lipidomics, which investigates lipid profiles, enhances our understanding of skin barrier functionalities and their perturbations in AD. This review synthesizes insights from these omics approaches, highlighting their collective importance in unraveling the intricate pathogenesis of AD. The review culminates by projecting future trajectories in AD research, particularly the promise of multi-omics in forging personalized medicine and novel therapeutic interventions. Such an integrated multi-omics strategy is poised to transform AD comprehension and management, steering towards more precise and efficacious treatment modalities.

RNA-sequencing of paired tape-strips and skin biopsies in atopic dermatitis reveals key differences

BACKGROUND

Skin tape-strips and biopsies are widely used methods for investigating the skin in atopic dermatitis (AD). Biopsies are more commonly used but can cause scarring and pain, whereas tape-strips are noninvasive but sample less tissue. The study evaluated the performance of skin tape-strips and biopsies for studying AD.

METHODS

Whole-transcriptome RNA-sequencing was performed on paired tape-strips and biopsies collected from lesional and non-lesional skin from AD patients (n = 7) and non-AD controls (n = 5). RNA yield, mapping efficiency, and differentially expressed genes (DEGs) for the two methods (tape-strip/biopsy) and presence of AD (AD/non-AD) were compared.

RESULTS

Tape-strips demonstrated a lower RNA yield (22 vs. 4596 ng) and mapping efficiency to known genes (28% vs. 93%) than biopsies. Gene-expression profiles of paired tape-strips and biopsies demonstrated a medium correlation (R2 = 0.431). Tape-strips and biopsies demonstrated systematic differences in measured expression levels of 6483 genes across both AD and non-AD samples. Tape-strips preferentially detected many itch (CCL3/CCL4/OSM) and immune-response (CXCL8/IL4/IL5/IL22) genes as well as markers of epidermal dendritic cells (CD1a/CD207), while certain cytokines (IL18/IL37), skin-barrier genes (KRT2/FLG2), and dermal fibroblasts markers (COL1A/COL3A) were preferentially detected by biopsies. Tape-strips identified more DEGs between AD and non-AD (3157 DEGs) then biopsies (44 DEGs). Tape-strips also detected higher levels of bacterial mRNA than biopsies.

CONCLUSIONS

This study concludes that tape-strips and biopsies each demonstrate respective advantages for measuring gene-expression changes in AD. Thus, the specific skin layers and genes of interest should be considered before selecting either method.

[Molecular diagnosis of hand eczema]

BACKGROUND

Because hand eczema is a diagnostic challenge even for experienced dermatologists, a correct diagnosis is essential to ensure success of specific therapies.

OBJECTIVES

Prerequisites for successful molecular diagnostics in general and in hand eczema in particular are discussed.

MATERIALS AND METHODS

Basic research and opinion statement on new developments in molecular diagnostics are considered with a special focus on hand eczema.

RESULTS

The first molecular classifier to distinguish psoriasis from (hand) eczema signature has been introduced as CE-marked in vitro diagnostics (CE-IVD); many more biomarkers associated with diagnostics, theranostics, or natural course of the disease are currently being investigated.

CONCLUSIONS

Diagnosis of hand eczema will be supported by molecular diagnostics in the near future; we are at the beginning of the molecular era in dermatology.