The inflammation in cutaneous lichen planus is dominated by IFN-ϒ and IL-21-A basis for therapeutic JAK1 inhibition

Type 2 Inflammation and Its Role in Dermatologic Diseases

Atopic dermatitis, prurigo nodularis, and chronic spontaneous urticaria are immune-mediated, inflammatory skin conditions characterized by intense itch and disease-specific skin lesions. Despite their different clinical presentations, the three diseases are unified by an aberrant type 2 immune response involving type 2 cytokines, immune cells, and sensory nerves that may underlie their shared clinical manifestations of inflammation and pruritus. The chronic nature of these conditions is associated with significant impairment in patients' quality of life and psychological disorders, such as anxiety and depression. This article reviews type 2 inflammation and its role in atopic dermatitis, prurigo nodularis, and chronic spontaneous urticaria, focusing on the pathophysiologic drivers of type 2 inflammation in each dermatologic condition. Understanding the shared immune mechanisms that underlie these seemingly distinct skin diseases and other concomitant inflammatory conditions is critical for applying therapeutic interventions targeting the type 2 immune pathway.

Inflammatory Skin Diseases: The Importance of Immunological Signatures

BACKGROUND

The understanding and classification of inflammatory skin diseases is shifting from a historical-descriptive perspective to a molecular-pathophysiological one based on immune response patterns. These are derived from a few key immunological mediators, each of which induces its own characteristic clinical, histopathological, and molecular patterns in the skin.

METHODS

This discussion of the definition of the immune response patterns of inflammatory skin diseases is based on information from pertinent publications retrieved by a selective literature search. A systematic literature search was also conducted on the response of inflammatory skin diseases to treatment with specific biologic agents.

RESULTS

The described immune response patterns are: autoinflammation; type 1, cytotoxic; type 2a, eczematous; type 2b, blistering; type 3, psoriasiform; type 4a, fibrosing; and type 4b, granulomatous. Each signature can usually be treated in a targeted manner. In general, each therapeutic target structure is associated with an adequate treatment response if and only if the skin disease under treatment has the relevant signature type. Hardly any biomarkers are currently available for the determination of immune response patterns in routine clinical practice.

CONCLUSION

The classification of inflammatory skin diseases by their immune response patterns opens up the prospect of specifically targeted immunotherapy for each immune response pattern regardless of the historical-descriptive disease entity. Targeting is intended to improve response rates. Initial findings suggest that this strategy is likely to succeed.

JAK Inhibitors and Inflammatory Nail Disorders: A Systematic Review of Clinical Outcomes and Therapeutic Potential

BACKGROUND

Inflammatory nail disorders can have a significant impact on patients' quality of life owing to aesthetic and functional concerns. They are also challenging to treat because the therapeutic armamentarium is quite limited. This systematic review aims to report the efficacy and safety of Janus kinase and Tyrosine kinase 2 inhibitors in treating these conditions.

METHODS

We conducted a comprehensive search on PubMed, Cochrane, and Embase Library to find eligible case reports, case series, single-arm clinical trials, and randomized controlled trials. We used the following search terms from inception until 15 December, 2024: "nail" AND "jak inhibitors" OR "tofacitinib" OR "baricitinib" OR "abrocitinib" OR "ruxolitinib" OR "deuruxolitinib" OR "upadacitinib" OR "ritlecitinib" OR "deucravacitinib" (nine searches in total).

RESULTS

Of 441 articles found, 31 were included in this study. The most extensively studied drug was tofacitinib, followed by baricitinib, deucravacitinib, upadacitinib, and abrocitinib. Janus kinase/Tyrosine kinase 2 inhibitors demonstrated improvements in inflammatory nail conditions, with generally mild adverse events (nasopharyngitis and transient laboratory abnormalities being most common). The topical formulation of tofacitinib, the only one studied in these nail diseases, also demonstrated promising results with minimal systemic absorption and no side effects.

CONCLUSIONS

This review highlights Janus kinase/Tyrosine kinase 2 inhibitors as a valuable addition to the therapeutic arsenal for inflammatory nail disorders while emphasizing the importance of safety assessments and tailored treatment approaches. The long-term safety of Janus kinase/Tyrosine kinase 2 inhibitors still needs further investigation and the potential for adverse events emphasizes the need for tailored therapeutic strategies, including more studies on topical formulations.

Hydroxychloroquine is safe and efficacious in oral lichen planus: data from a large outpatient cohort

Lichen planus (LP) is a chronic inflammatory T-cell mediated disease affecting the skin, mucous membranes and skin appendages. Data on clinical phenotypes and systemic treatment of LP are limited. We analyzed a cohort of LP patients (equal or older than 18 years) regarding their clinical phenotypes (subtype, demographics, comorbidities) and treatment. Patients were selected from 2017 to 2023 who were seen in our outpatient clinic during a treatment period of at least 2 years. We identified 85 patients (62 females, 73% and 76 above 50 years; 89%) who met selection criteria. 33 had oral LP (39%), 23 had cutaneous LP (27%) and 2% had both or other manifestations (32%). Frequent comorbidities were hypertension (n = 40), hypothyroidism (n = 17), asthma (n = 11), diabetes (n = 10) and dyslipidemia (n = 8). 44% were taking a medication known to favor LP onset. 2/85 patients had a malignant transformation. 33 patients were treated topically and 50 required systemic therapy. Hydroxychloroquine (HCQ) (n = 18; 36%) and retinoids (n = 17; 34%) were the most commonly used systemic medications. Both were efficacious as determined by the investigator global response reaching rates 78% and 71%, respectively. The tolerability of retinoids was lower than HCQ (adverse event rate 29% versus 6%). Our results confirm previous data on clinical phenotypes and comorbidity patterns in LP patients. The treatment assessment suggests that HCQ may be an efficacious and safe first-line treatment for mucosal lichen planus. Further data from prospective controlled clinical trials are needed to prove the optimal treatment approach for different clinical phenotypes of LP.

The association of C-reactive protein to albumin ratio wıth lichen planus

OBJECTIVE

In some diseases associated with inflammation, the C-reactive protein-to-albumin ratio can be used as a biomarker of inflammation. Since lichen planus is a chronic inflammatory disease, our study aimed to investigate the relationship between C-reactive protein-to-albumin ratio and disease activity and whether it plays a role in determining disease prognosis, and compare them with those in subjects without lichen planus.

METHODS

This is a case-control study. Demographic data, clinical features, and laboratory measures, including neutrophil, lymphocyte, eosinophil, platelet counts, neutrophile-to-lymphocyte ratio, erythrocyte sedimentation rate, C-reactive protein, albumin, and C-reactive protein-to-albumin ratio were statistically compared between patients with lichen planus (n=61) and controls (n=64).

RESULTS

Albumin and erythrocyte sedimentation rate (p<0.001), C-reactive protein (p=0.017), C-reactive protein-to-albumin ratio (p=0.016), and neutrophile-to-lymphocyte ratio (p=0.02) were significantly higher in the patient group than in the control group. C-reactive protein-to-albumin ratio (p=0.003, OR 1.2), neutrophile-to-lymphocyte ratio (p=0.02, OR 1.4), and erythrocyte sedimentation rate (p=0.003, OR 1.1) were effective in differentiating patients from the healthy group. Erythrocyte sedimentation rate>4.5 mm/h, C-reactive protein-to-albumin ratio>0.6, and neutrophile-to-lymphocyte ratio>1 were useful in showing disease activity, of which C-reactive protein-to-albumin ratio has the best value with 92% sensitivity. C-reactive protein-to-albumin ratio has a sensitivity of 100% and is more effective and sensitive than other markers in distinguishing between mild and severe groups and between single and multiple involvement.

CONCLUSION

Elevated C-reactive protein-to-albumin ratio levels may be considered a potential marker for lichen planus. It may be highly sensitive to follow-up of systemic inflammation and disease activity in patients with lichen planus. However, further prospective studies may confirm the association between C-reactive protein-to-albumin ratio and lichen planus.

Therapy resistant hypertrophic lichen planus and its response to oral tofacitinib with a priori tissue cytokine expression: a real-world hospital-based study

BACKGROUND

Although there are several reports on use of tofacitinib in lichen planus (LP), its usage in hypertrophic LP is sparse with no data on tissue cytokine expression.

METHODS

We retrospectively analyzed the records of recalcitrant hypertrophic LP patients treated with tofacitinib monotherapy. Demographic and clinical details were noted. We assessed Th1, Th2, Th17 cytokines in lesional and non-lesional tissue samples using real time PCR. Dose, duration and response to tofacitinib in terms of resolution of lesions and pruritus was noted. Side effects and time after which relapses were seen post treatment were recorded.

RESULTS

Fifteen hypertrophic LP patients were analysed with a mean age of 34.06years (18-59years, 8 females and 7 males). Previous failed systemic treatments included corticosteroids(n = 1), retinoids(n = 5), cyclosporine(n = 8), methotrexate(n = 8) and thalidomide(n = 3). Tissue cytokine analysis was performed in 3/15 patients which showed upregulation of Th1 and Th17 cytokines [Interferon-γ, Interleukin (IL)-17 and IL-21]. Mean dose of tofacitinib was 11.6 mg (10-15 mg) and was given for a mean duration of 8.8weeks (8-16weeks). Pruritus resolved in a mean duration of 8.6days and mean time to achieve resolution of lesions was 4.69weeks. Two patients failed to show improvement and drug was stopped after 8 weeks. Side effects were noted in 6 patients [dyslipidemia(n = 2), upper respiratory infection(n = 2), fever(n = 1) and folliculitis(n = 1)]. Relapse was noted in 5/13 patients [38.46%, mean time duration: 7.2weeks (4-12weeks)].

CONCLUSION

A predominant Th1/Th17 cytokine profile was noted in the subset analysed and was extrapolated to the use of oral tofacitinib in hypertrophic LP patients.

Off-label use of JAK1 inhibitor upadacitinib in dermatology

Upadacitinib, a selective Janus kinase 1 (JAK1) inhibitor, has gained FDA approval for conditions such as rheumatoid arthritis and atopic dermatitis. Emerging studies suggest its potential for off-label use in various dermatological disorders. This review systematically explores the off-label dermatological applications of upadacitinib. We conducted a comprehensive literature search across MEDLINE, EMBASE, SCOPUS, and ClinicalTrials.gov. Studies on alopecia areata, hidradenitis suppurativa, vitiligo, and other conditions were included. The review identified two randomized controlled trials (RCTs) evaluating upadacitinib's efficacy in hidradenitis suppurativa and vitiligo. Both trials demonstrated promising improvements in clinical outcomes, though some results were not statistically significant. Additionally, case reports and series highlight its efficacy in alopecia areata and lichen planus. These findings suggest upadacitinib as a viable option for refractory dermatological conditions. However, the limited sample sizes and short follow-up periods underscore the need for further large-scale, long-term studies.

Janus kinase 1 inhibitor abrocitinib for isolated nail lichen planus: a case report and literature review

AIM

This study aims to evaluate the efficacy and safety of the Janus kinase 1 (JAK1) inhibitor abrocitinib for treating nail lichen planus (NLP) and to review available case reports documented in English.

METHODS

We reported the first case of a patient with isolated NLP treated with the selective JAK1 inhibitor abrocitinib. The patient received 100 mg of oral abrocitinib daily.

RESULTS

After 6 months, the patients showed 82.35% improvements in the Dermatology Life Quality Index (DLQI) and 79.17% improvement in the Nail lichen planus severity index (tNLPSI), which were consistent with the clinical improvement, correlating with clinical improvement. In the subsequent 6 months, the dose was reduced to 100 mg every other day, with further improvement in onycholysis.

CONCLUSIONS

This case suggests that abrocitinib can be both safe and effective for treating NLP.

Rapid response of lichen planus to baricitinib associated with suppression of cytotoxic CXCL13+CD8+ T cells

BACKGROUNDCutaneous lichen planus (LP) is a recalcitrant, difficult-to-treat, inflammatory skin disease characterized by pruritic, flat-topped, violaceous papules on the skin. Baricitinib is an oral Janus kinase (JAK) 1/2 inhibitor that interrupts the signaling pathway of IFN-γ, a cytokine implicated in the pathogenesis of LP.METHODSIn this phase II trial, 12 patients with cutaneous LP received 2 mg daily baricitinib for 16 weeks, accompanied by in-depth spatial, single-cell, and bulk transcriptomic profiling of pre- and posttreatment samples.RESULTSAn early and sustained clinical response was seen, with 83.3% of patients responsive at week 16. Our molecular data identified a unique, oligoclonal IFN-γ, CD8+, and CXCL13+ cytotoxic T cell population in LP skin and demonstrated a rapid decrease in IFN signature within 2 weeks of treatment, most prominently in the basal layer of the epidermis.CONCLUSIONThis study demonstrates the efficacy and molecular mechanisms of JAK inhibition in LP.TRIAL REGISTRATIONNCT05188521FUNDINGEli Lilly, Appignani Benefactor Funds, 5P30AR075043, Mayo Clinic Clinical Trials Stimulus Funds.

Lichen planus-the role of age and gender in clinical appearance and treatment : A narrative review

Lichen planus is a common pruritic inflammatory disorder of the skin with an autoimmune background. It affects < 1% of the general population. The disease has significant comorbidities that must be considered in a holistic approach. Skin and skin adnexa, mucosa, eyes, and the esophagus may be affected. There are various clinical subtypes in addition to classical cutaneous lichen planus. These subtypes depend on age and gender. Nail involvement can result in functional and psychological impairment. Lichen planopilaris in adults leads to irreversible cicatrical alopecia. Erosive and ulcerated lichen planus of the mucosa carries an increased risk of malignant transformation, at least in adults. Treatment must consider the affected area, the severity of disease, age, gender, and comorbidities.

Th Pathways in Immune-Mediated Skin Disorders: A Guide for Strategic Treatment Decisions

In recent years, there have been significant breakthroughs in the identification of immunological components of skin diseases and in the development of immunomodulatory drugs. Novel therapies create exciting prospects for personalized care. This article provides an overview of the role played by Th1, Th2, Th17, and follicular Th pathways in the most common skin diseases. Additionally, it elucidates the impact of current and upcoming treatments on each of these signaling cascades. Skin diseases predominantly influenced by a single dominant Th pathway such as psoriasis and atopic dermatitis are well-suited for biologics. However, in many other disorders a complex interplay between different immune pathways exists. This can lead to inconsistent efficacy of biologics based on individual patient profiles. In case of activation of several Th pathways, it may be more suitable to consider conventional therapies or JAK inhibitors. Increasing immunological insights have transitioned from laboratory research to practical applications, a trend that is expected to continue growing in the future.

A Case of Extensive Lichen Planus Treated With Deucravacitinib

Lichen planus (LP) is a persistent inflammatory condition that affects the skin and mucous membranes, often significantly impacting quality of life. Recent research has highlighted the potential of Janus kinase (JAK) inhibitors as an effective treatment for LP. We report a case of a 52-year-old woman with a history of hypertension, obesity, and hypothyroidism who presented with a widespread, itchy, and scaly rash that was present for one month and affected 80% of her body surface area (BSA). A biopsy from the right lower extremity confirmed LP. After two months of treatment with deucravacitinib, the patient demonstrated significant improvement, with BSA involvement reduced to 20% and erythema notably diminished. To our knowledge, this is the first documented case of extensive cutaneous LP successfully managed with deucravacitinib. Unlike other JAK inhibitors, deucravacitinib selectively targets tyrosine kinase 2 (Tyk2), offering focused modulation of the immune response while minimizing broader adverse effects. This specificity provides deucravacitinib with a more favorable safety profile, making it a potentially ideal option for the long-term management of chronic dermatologic conditions like LP, which often require extended treatment.

Pathogenic relevance of antibodies against desmoglein 3 in patients with oral lichen planus

BACKGROUND AND OBJECTIVES

Oral lichen planus (OLP) is a T cell driven disorder that significantly impairs patients' quality of life. Previous reports suggest that both cellular and humoral activities against desmoglein (dsg) 1 and 3 may be involved in OLP pathogenesis. Here, we aim to analyze the frequency of occurrence and pathological significance of anti-dsg antibodies in a large cohort of OLP patients.

MATERIALS AND METHODS

OLP patients were screened for anti-dsg antibodies by enzyme-linked immunosorbent assay in three tertiary referral centers. OLP sera with anti-dsg antibodies were further analyzed by Western blot and dispase-based keratinocyte dissociation assay (DDA) to identify the targeted dsg ectodomains and to assess their pathogenicity.

RESULTS

Of 151-screened individuals with OLP, only four patients (2.6%) with erosive OLP showed serum IgG against dsg1/3. Western blot analysis with recombinant dsg3 ectodomains revealed preferential recognition of the extracellular domain 5. By DDA with spontaneously immortalized human keratinocytes, none of the sera from these four patients induced acantholysis.

CONCLUSIONS

Activation of humoral immunity occurs prevalently in patients with erosive OLP, probably due to epitope spreading. OLP serum antibodies are unable to induce loss of intercellular adhesion in vitro, strongly suggesting that they are not disease causing but rather an epiphenomenon.

[Janus kinase inhibitors for skin disorders]

Immune factors such as interferon‑ɣ and interleukin 4 belong to the group of cytokines that are dependent on type I/II receptors for their signal transmission. Upon activation, these receptors transmit their signal to the cell nucleus and, thus, modulate gene transcription via a signaling cascade consisting of Janus kinases (JAK). This family of four kinases (JAK 1, JAK 2, JAK 3, and tyrosine kinase 2 (TYK2)) subsequently activate members of the signal transducer and activator of transcription (STAT). This finding turned the JAK/STAT signaling pathway into a pharmacological target for the treatment of inflammatory diseases in which cytokines using type I/II receptors play a pathogenic role. In 2018, the European Medicines Agency (EMA) approved tofacitinib for the treatment of psoriatic arthritis. This was the first approval of a JAK/STAT pathway inhibitor for patients treated by dermatologists and rheumatologists. Since then, several new JAK inhibitors have been approved for dermatologic diseases such as atopic dermatitis, alopecia areata, vitiligo, and plaque-type psoriasis. In addition, JAK inhibitors are being investigated for the treatment of many other skin diseases. Thus, systemic JAK inhibitors complete the spectrum of immunotherapeutics with a broader immunological approach compared to monoclonal antibodies. The low molecular weight of JAK inhibitors enables the preparation of these drugs for both systemic and topical administration. Their utilization could represent a valuable alternative to topical steroids. The safety profile of JAK inhibitors must be taken into account. Possible long-term effects may become apparent in the next few years. This article describes both approved JAK inhibitors and relevant new JAK inhibitors that are promising candidates for approval as therapeutics in dermatology.

Distinct Variations in Gene Expression and Cell Composition across Lichen Planus Subtypes

Lichen planus (LP) is a highly prevalent inflammatory skin disease. While various clinical subtypes have been defined, detailed comparisons of these variants are lacking. This study aimed to elucidate differences in gene expression and cellular composition across LP subtypes. Lesional skin biopsies from 28 LP patients (classical, oral, genital, and lichen planopilaris) and seven non-diseased skin controls (NDC) were analyzed. Gene expression profiling of 730 inflammation-related genes was conducted using NanoString. Immune cell compositions were assessed by multiplex immunohistochemistry. Gene expression profiles revealed unique inflammatory signatures for each LP subtype. Lichen planopilaris exhibited the most divergence, with downregulated gene expression and upregulation of complement pathway genes (C5-7), along with elevated M2 macrophages. Oral and genital LP demonstrated similar profiles with strong upregulation of TNF-related and Toll-like receptor-associated genes. Oral LP showed the highest upregulation of cytotoxicity-associated genes, as well as high numbers of CD8+ IL-17A+ (Tc17) cells (8.02%). Interferon gene signatures were strongly upregulated in oral and classical LP. The study highlights distinct differences in inflammatory gene expression and cell composition across LP subtypes, emphasizing the need for tailored therapeutic approaches.

Lichen Planus: What is New in Diagnosis and Treatment?

Lichen planus (LP), an idiopathic, multifaceted chronic inflammatory disease with a heterogeneous clinical presentation, affects approximately 0.5-1% of the population. The various clinical manifestations of LP fall into three broad categories, namely cutaneous, appendageal, and mucosal, with further subclassification depending on the morphology and distribution patterns of individual lesions. There is mounting evidence that LP has systemic associations, including autoimmune conditions, glucose intolerance, dyslipidemia, and cardiovascular disorders. Cutaneous hypertrophic and mucosal forms of LP are at a heightened risk for malignant transformation. Familiarity with these potential associations in conjunction with long-term follow-up and regular screening could lead to a timely diagnosis and management of concomitant conditions. In addition, the frequent quality of life (QoL) impairment in LP underscores the need for a comprehensive approach including psychological evaluation and support. Several treatment strategies have been attempted, though most of them have not been adopted in clinical practice because of suboptimal benefit-to-risk ratios or lack of evidence. More recent studies toward pathogenesis-driven treatments have identified Janus kinase inhibitors such as tofacitinib, phosphodiesterase-4 inhibitors such as apremilast, and biologics targeting the interleukin-23/interleukin-17 pathway as novel therapeutic options, resulting in a dramatic change of the treatment landscape of LP. This contemporary review focuses on the diagnosis and management of LP, and places emphasis on more recently described targeted treatment options.

Association of lichen planus with asthma and allergic rhinitis in the All of Us Research Program: a cross-sectional study

In this study, lichen planus was found to be associated with asthma and allergic rhinitis, highlighting a possible shared immunopathogenesis. In this population-based cross-sectional study, the association remained after controlling for covariates.

Network pharmacology and molecular docking analysis predict the mechanisms of Huangbai liniment in treating oral lichen planus

This study explored the mechanism of Huangbai liniment (HB) for the treatment of oral lichen planus (OLP) through network pharmacology and molecular docking techniques. The study identified HB' active ingredients, therapeutic targets for OLP, and associated signaling pathways. The chemical composition of HB was screened using the HERB database. The disease targets of OLP were obtained through the GeneCards and OMIM databases. A protein-protein interactions network was constructed with the String platform. Topological analysis was performed using Cytoscape software to identify core targets. Gene ontology and Kyoto encyclopedia of genes and genomes pathway enrichment analysis were performed using the Hiplot database, and the active ingredients and core targets were verified by molecular docking. Date analysis showed that the active composition of HB in the treatment of OLP were quercetin, wogonin, kaempferol, and luteolin. This survey identified 10 potential therapeutic targets, including TNF, CXCL8, IL-6, IL1B, PIK3R1, ESR1, JUN, AKT1, PIK3CA, and CTNNB1. Molecular docking revealed stable interactions between OLP' key targets and HB. These key targets were predominantly involved in the PI3K-Akt signaling pathway, AGE-RAGE signaling pathway, TNF signaling pathway, and HIF-1 signaling pathway. HB plays a crucial role in the treatment of OLP, acting on multiple targets and pathways, particularly the PI3K-Akt signaling pathway. It regulated biological processes like the proliferation of epithelial cells and lymphocytes and mediates the expression of transcription factors, cytokines, and chemokines. Therefore, this study provides a theoretical basis for the clinical trial and application of HB in the therapy of OLP.

Case report: Hypertrophic lichen planus initially misdiagnosed as squamous cell carcinoma

Fewer than 26 case reports describe hypertrophic lichen planus (HLP) misdiagnosed as cutaneous squamous cell carcinoma (cSCC). It can be difficult to distinguish between HLP and cSCC, as these two conditions share many clinical and histopathological characteristics. Patients who are misdiagnosed with cSCC often undergo unnecessary medical and/or surgical interventions before receiving a diagnosis of HLP and improving on HLP-directed therapy. This case series highlights the course of three female patients, referred to a single tertiary institution between 2018 and 2022, who were initially misdiagnosed with cSCC before receiving a diagnosis of HLP. We have emphasized the clinical and histopathological distinguishing features between HLP and cSCC, the pathogenesis of HLP, and current and new HLP-directed therapy. We hope that this case series serves as a reminder to dermatologists, dermatologic surgeons, and dermatopathologists to be aware of this diagnostic challenge.

TYK2 inhibition with deucravacitinib ameliorates erosive oral lichen planus

Erosive oral lichen planus (OLP) is a challenging disease. This T cell driven disorder frequently shows a treatment unresponsive course and strongly limits patients' quality of life. The disease lacks FDA or EMA approved drugs for its treatment and the efficacy of the commonly administered treatments (i.e. topical and systemic steroids, steroid sparing agents) is often only partial. Although the etiopathogenesis of the disease still needs to be fully elucidated, recent advances helped to identify interferon-ɣ (IFN-ɣ) as a pivotal cytokine in OLP pathogenesis, thus making the interference with its signalling a therapeutic target. Janus kinase (JAK) inhibitors therefore gained relevance for their inhibitory effect on IFN-ɣ signalling. While some drugs such as abrocitinib, upadacitinib, tofacitinib directly interfere with IFN-ɣ signalling through blockade of JAK1 and/or JAK2, deucravacitinib, a selective TYK-2 inhibitor indirectly interferes on IFN-ɣ activation through interference with interleukin (IL)-12, a potent promotor for Th1/IFN-ɣ responses. This mechanism of action makes deucravacitinib a candidate drug for the treatment of OLP. Here we provide initial evidence that deucravacitinib 6 mg daily has a beneficial effect in three patients with oral OLP.

Integrative Approaches for the Diagnosis and Management of Erosive Oral Lichen Planus

Erosive oral lichen planus (EOLP) represents a significant challenge in dental and medical management due to its chronic inflammatory nature, painful symptoms, and impact on quality of life. This study aims to evaluate the current diagnostic approach with novel non-invasive techniques, such as dermoscopy, and also the landscape of treatment options for EOLP, focusing on its efficacy, safety, and the challenges that it present in clinical practice. Through a comprehensive literature review, we explored the use of topical corticosteroids, systemic immunosuppressants, biologics, and Janus kinase (JAK) inhibitors in treating EOLP, alongside examining patient compliance, psychological impacts, and the risk of adverse effects and recurrence. Our findings reveal that while topical corticosteroids are the cornerstone of EOLP treatment, offering symptomatic relief, their long-term use is limited by side effects and tolerance development. Systemic therapies and biologics provide alternatives for refractory cases but necessitate careful adverse effect monitoring. JAK inhibitors show promise as an innovative treatment avenue but require more evidence on long-term safety and efficacy. This study highlights the necessity of personalized treatment approaches due to the variable disease course and response to treatment, underscoring the importance of a multidisciplinary strategy in managing EOLP. The complexity of EOLP treatment, compounded by its psychological and quality of life impacts, demands ongoing research into targeted therapies, the establishment of standardized treatment protocols, and the development of effective outcome measures to improve patient care and treatment outcomes.

Oral Baricitinib in the Treatment of Cutaneous Lichen Planus

Background

Cutaneous lichen planus (LP) is a recalcitrant, difficult-to-treat, inflammatory skin disease characterized by pruritic, flat-topped, violaceous papules on the skin. Baricitinib is an oral Janus kinase (JAK) 1/2 inhibitor that interrupts the signaling pathway of interferon (IFN)-γ, a cytokine implicated in the pathogenesis of LP.

Methods

In this phase II trial, twelve patients with cutaneous LP received baricitinib 2 mg daily for 16 weeks, accompanied by in-depth spatial, single-cell, and bulk transcriptomic profiling of pre-and post-treatment samples.

Results

An early and sustained clinical response was seen with 83.3% of patients responsive at week 16. Our molecular data identified a unique, oligoclonal IFN-γ, CD8+, CXCL13+ cytotoxic T-cell population in LP skin and demonstrate a rapid decrease in interferon signature within 2 weeks of treatment, most prominent in the basal layer of the epidermis.

Conclusion

This study demonstrates the efficacy and molecular mechanisms of JAK inhibition in LP. Trial Registration Number : NCT05188521.

Human papilloma virus-16-specific CD8+ T-cell expansions characterize different clinical forms of lichen planus and not lichen sclerosus et atrophicus

Lichen planus (LP) is a cutaneomucosal chronic inflammatory disease characterized by a CD8+ cytotoxic T-lymphocytes (CTL) infiltrate. In erosive oral LP, we found HPV16-specific activated CTL in lesions, supporting a pathogenic contribution of HPV16. Here, we investigated whether a similar scenario occurs in other clinical forms of LP and in lichen sclerosus et atrophicus (LSA), another chronic disease also affecting the mucosa and/or the skin. Blood CTL from LP and LSA patients expressed significant higher levels of granzyme B, perforin and CD107a proteins than healthy donors. Expansions of TCRVß3+ CTL, with presence of TCR clonotypes identical to those previously detected in erosive oral LP, were found both in blood and mucosal/skin lesions of LP, and not of LSA patients. These expansions were enriched with HPV16-specific CD8+ T-cells as shown by their recognition of the E711-20 immunodominant epitope. In LSA patients, the peripheral repertoire of CTL was oligoclonal for TCRVß6+ CTL. Finally, although patients with LP and LSA have developed antibodies against HPV16 capsid L1, antibodies against HPV16 E6 were only observed in patients with LP. Overall, our data collectively suggest an involvement of HPV16-specific CTL in different clinical forms of LP, not only in erosive oral LP, while a different scenario operates in LSA.

The Use of Janus Kinase Inhibitors for Lichen Planus: An Evidence-Based Review

BACKGROUND

Lichen Planus (LP) is a dermatological disorder characterized by violaceous papules that affect the cutaneous region, nails, scalp, and mucous membranes. Current molecular and clinical studies point to the Janus Kinase-signal transducer and activator of transcription (JAK-STAT) pathway as a potential effector of LP pathology.

OBJECTIVE

This systematic review summarizes the current reported literature outcomes for patients receiving JAK inhibitors to treat LP.

METHODS

MEDLINE and Embase were searched on 16 October, 2022, and 15 original articles were included, with 56 LP patients.

RESULTS

(mean age: 54.5 years, range: 26-81 years, male: 26.8%). The treatment outcomes were included for the following JAK inhibitors: tofacitinib (n = 30), baricitinib (n = 16), ruxolitinib (n = 12), and upadacitinib (n = 2). Patient outcomes were classified into complete resolution, partial resolution, and no resolution. Patients achieving complete resolution represented 25% (n = 4/16) in the baricitinib group, 10% (n = 3/30) in the tofacitinib group, 16.7% (n = 2/12) in the ruxolitinib group, and 100% (2/2) in the upadacitinib group. Partial resolution patients represented 31.3% (n = 5/16) of baricitinib patients, 60% (n = 18/30) of tofacitinib patients, and 83% (n = 10/12) of ruxolitinib patients. 43.8% (n = 7/16) of baricitinib patients and 10% (n = 9/30) of tofacitinib patients had no resolution of lesions.

CONCLUSION

This review also highlights the significance of utilizing a uniform outcome measure for LP, as it aids in reporting more generalizable results, reduces reporting bias, and ultimately lead to improved clinical outcomes for LP patients.

Comprehensive Insight into Lichen Planus Immunopathogenesis

Lichen planus is a chronic disease affecting the skin, appendages, and mucous membranes. A cutaneous lichen planus is a rare disease occurring in less than 1% of the general population, while oral illness is up to five times more prevalent; still, both forms equally impair the patient's quality of life. The etiology of lichen planus is not entirely understood. Yet, immune-mediated mechanisms have been recognized since environmental factors such as hepatitis virus infection, mechanical trauma, psychological stress, or microbiome changes can trigger the disease in genetically susceptible individuals. According to current understanding, lichen planus immunopathogenesis is caused by cell-mediated cytotoxicity, particularly cytotoxic T lymphocytes, whose activity is further influenced by Th1 and IL-23/Th-17 axis. However, other immunocytes and inflammatory pathways complement these mechanisms. This paper presents a comprehensive insight into the actual knowledge about lichen planus, with the causal genetic and environmental factors being discussed, the immunopathogenesis described, and the principal effectors of its inflammatory circuits identified.

Cutaneous lichenoid drug eruptions: A narrative review evaluating demographics, clinical features and culprit medications

Cutaneous lichenoid drug eruptions (LDE) are adverse drug reactions (ADR) characterized by symmetric, erythematous, violaceous papules reminiscent but rarely fully characteristic of lichen planus (LP). We aimed to analyse the literature describing cases of LDE within the last 20 years to provide additional insight into culprit drugs, typical latency to onset of the eruption, the spectrum of clinical presentations, severity and management. A literature search was conducted in MEDLINE between January 2000 and 27 January 2021. The keywords 'lichenoid drug rash' and 'lichenoid drug eruption' were used. Cases were included if LDE diagnosis was made, and culprit drugs were identified. A total of 323 cases with LDE were identified from 163 published case reports and studies. The mean patient age was 58.5 years (1 month to 92 years), and 135 patients (41.8%) were female. Checkpoint inhibitors (CKI) were the most frequently reported culprit drugs (136 cases; 42.1%), followed by tyrosine kinase inhibitors (TKI) (39 cases; 12.0%) and anti-TNF-α-monoclonal antibodies (13 cases; 4.0%). The latency between initiation of the drug and manifestation was 15.7 weeks (range: 0.1-208 weeks). After discontinuing the culprit drug, the median time to resolution was 14.2 weeks (range: 0.71-416 weeks). One hundred thirty-six patients (42.1%) were treated with topical, and 54 patients (16.7%) with systemic glucocorticoids. Overall, we conclude that, albeit rare, LDE is challenging to diagnose ADR induced by mostly CKI, TKI, and biologics. Treatment modalities resemble that of lichen planus, and the culprit drugs had to be discontinued in only 26%, which is low compared with other types of adverse drug reactions. This is probably due to the low risk of aggravation (e.g. toxic epidermal necrolysis) if the drug is continued and the benefit/risk ratio favouring the drug, as is often the case in cancer therapy.

Therapeutic strategies for oral lichen planus: State of the art and new insights

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa. Several clinical subtypes of OLP have been reported, including the reticular and erosive one. On the one hand, reticular OLP is usually asymptomatic and is characterized by white streaks surrounded by well-defined erythematous borders. On the other hand, erosive OLP shows ulcerations and erosions surrounded by erythematous mucosa. While reticular OLP is relatively easy to control, erosive OLP is extremely painful and refractory to therapies, limiting the quality of life of the patients. In addition, treating erosive OLP is extremely tricky, and a gold standard treatment has not yet been established. However, several therapeutic approaches have been reported as effective, including systemic corticosteroids, systemic retinoids, and anti-interleukin (IL)-17/anti-IL-23 drugs. Indeed, our group and other several authors reported the effectiveness of anti-IL17, anti-IL12/23, and anti-IL23 agents in refractory OLP, highlighting the urgency of clinical studies on the use of anti-IL agents in OLP patients. In this paper, we reviewed the English- and German-language literature about therapeutic strategies for treating OLP, focusing on new systemic therapies for erosive OLP.

[Mucosal lichen planus-a diagnostic and therapeutic challenge]

Mucosal lichen planus (MLP) is a chronic inflammatory disease of the mucosa. This condition can affect the mouth, esophagus, pharynx, genitalia, anus, and conjunctiva. This disease shows a tendency to chronicity with phases of relapses for a duration of 3-10 years. It presents with varying morphologies including lacy or fern-like, slightly raised striae, erosions, erythema, and atrophy. The pathophysiology is not yet fully understood and is dominated by the classic band-like lymphocytic infiltrate along the dermoepidermal junction. MLP is very challenging to treat, since the clinical course entails frequent relapses and shows resistance to therapy. The most commonly used local treatments are topical corticosteroids or calcineurin inhibitors. In addition to systemic glucocorticosteroids and traditional systemic drugs such as oral retinoids or methotrexate, emerging anti-inflammatory therapies such as Janus kinase inhibitors and biologics may be promising and are currently being evaluated in clinical trials.

JAK inhibitors in lichen planus: A review of pathogenesis and treatments

Lichen planus (LP) is an auto-inflammatory skin disorder identified by a presence of T-cell lymphocytes at the dermal-epidermal junction. It is hypothesized that the INF-γ/CXCL10 axis fulfills a major role in the onset and persistence of chronic inflammation in LP. Since Janus kinases (JAKs) are involved in the transduction of INF-γ signals, they may be good targets for LP treatment. Several case reports and case series described the safety and efficacy of upadacitinib (2 articles), tofacitinib (6 articles), baricitinib (4 articles), and Ruxolitinib (1 Article) in the treatment of LP variants. The predominant variants that JAK inhibitors improved were lichen planopilaris, nail LP, and erosive LP. Considering the role of the JAK pathway in LP pathogenesis and the evidence provided by these reports, it seems JAK inhibitors would be effective therapeutic agents for LP treatment. Hence, these agents should be trialed and evaluated further.

Lichen planus in Deutschland - Epidemiologie, Behandlung und Komorbidität. Eine retrospektive Krankenkassendatenanalyse

HINTERGRUND UND ZIELE

Lichen planus (LP) ist eine chronisch entzündliche Hauterkrankung, die eine große Belastung für die betroffenen Patienten darstellt. Es liegen jedoch nur wenige Daten zu dieser Erkrankung vor. Ziel dieser Studie ist es, das Wissen über die Epidemiologie und die Behandlungsmuster des LP anhand von Abrechnungsdaten deutscher Krankenkassen zu erweitern.

PATIENTEN UND METHODEN

Diese retrospektive Beobachtungsstudie nutzte die InGef-Forschungsdatenbank. Es wurden prävalente und inzidente LP-Patienten aus den Jahren 2015 und 2018 identifiziert. Für demografische Charakteristika, Behandlungsmuster und Komorbidität wurden deskriptive Statistiken berechnet.

ERGEBNISSE

Die Prävalenz des LP lag bei 95,9 und die Inzidenz bei 20,1 pro 100 000 Personen im Jahr 2018, was 79 605 prävalenten LP-Fällen in Deutschland entspricht. Die erste LP-Diagnose wurde in der Regel von einem Dermatologen oder Hausarzt gestellt. Drei Viertel der inzidenten und die Hälfte der prävalenten Patienten erhielten eine topische Therapie, meist ohne zusätzliche systemische Therapie. Die Komorbidität des LP stand im Einklang mit bereits bekannten Assoziationen.

SCHLUSSFOLGERUNGEN

Die verfügbaren Therapieoptionen sind nach wie vor begrenzt, was den ungedeckten Bedarf an sicheren und wirksamen systemischen Behandlungsmodalitäten unterstreicht. Der LP ist häufig mit klinisch relevanter systemischer Komorbidität verbunden. Zusammengenommen könnten diese Beobachtungen zu einem verbesserten Verständnis der Krankheitslast führen und das diagnostische Bewusstsein für diese Erkrankung unter Klinikern schärfen.

Lichen planus in Germany - epidemiology, treatment, and comorbidity. A retrospective claims data analysis

BACKGROUND AND OBJECTIVES

Lichen planus (LP) is a chronic inflammatory skin disease and is a major burden for affected patients. However, data on this condition are scarce. This study aims to expand the knowledge on the epidemiology and treatment patterns of LP using German health claims data.

PATIENTS AND METHODS

This retrospective observational study was based on the InGef research database. Prevalent and incident LP patients were identified in the years 2015 and 2018. Descriptive statistics were calculated for demographic characteristics, treatment patterns, and comorbidity.

RESULTS

The prevalence of LP was 95.9 and the incidence was 20.1 per 100,000 individuals in 2018, corresponding to 79,605 prevalent LP cases in Germany. The first LP diagnosis was generally documented by a dermatologist or a primary care physician. Three-quarters of the incident and half of the prevalent patients received topical therapy, mostly without further systemic therapy. Comorbidity in LP patients was consistent with previously known associations.

CONCLUSIONS

Available treatment options remain limited, underscoring the unmet need for safe and efficacious systemic treatment modalities. Lichen planus is frequently accompanied by clinically relevant systemic comorbidity. Taken together, these observations may improve our understanding of the burden of this disease and increase diagnostic awareness among clinicians.

Integrated bioinformatic analysis of gene expression profiling data to identify combinatorial biomarkers in inflammatory skin disease

Selection of appropriate biomarker to identify inflammatory skin diseases is complicated by the involvement of thousands of differentially expressed genes (DEGs) across multiple cell types and organs. This study aimed to identify combinatorial biomarkers in inflammatory skin diseases. From one gene expression microarray profiling dataset, we performed bioinformatic analyses on dataset from lesional skin biopsies of patients with inflammatory skin diseases (atopic dermatitis [AD], contact eczema [KE], lichen planus [Li], psoriasis vulgaris [Pso]) and healthy controls to identify the involved pathways, predict upstream regulators, and potential measurable extracellular biomarkers. Overall, 434, 629, 581, and 738 DEGs were mapped in AD, KE, Li, and Pso, respectively; 238 identified DEGs were shared among four different inflammatory skin diseases. Bioinformatic analysis on four inflammatory skin diseases showed significant activation of pathways with known pathogenic relevance. Common upstream regulators, with upregulated predicted activity, identified were CNR1 and BMP4. We found the following common serum biomarkers: ACR, APOE, ASIP, CRISP1, DKK1, IL12B, IL9, MANF, MDK, NRTN, PCSK5, and VEGFC. Considerable differences of gene expression changes, involved pathways, upstream regulators, and biomarkers were found in different inflammatory skin diseases. Integrated bioinformatic analysis identified 12 potential common biomarkers of inflammatory skin diseases requiring further evaluation.

Thiol-Disulfide Homeostasis in Skin Diseases

Oxidative stress represents the imbalance between oxidants and antioxidants and has been associated with a wide range of diseases. Thiols are the most important compounds in antioxidant defense. There is an equilibrium between thiols and their oxidized forms, disulfides, known as dynamic thiol-disulfide homeostasis (TDH). In 2014, Erel and Neselioglu developed a novel automated assay to measure thiol and disulfide levels. Subsequently, many researchers have used this simple, inexpensive and fast method for evaluating TDH in various disorders. We have reviewed the literature on the role of TDH in skin diseases. We identified 26 studies that evaluated TDH in inflammatory diseases (psoriasis, seborrheic dermatitis, atopic dermatitis, vitiligo, acne vulgaris and rosacea), allergic diseases (acute and chronic urticaria) and infectious diseases (warts, pityriasis rosea and tinea versicolor). The results are heterogeneous, but in most cases indicate changes in TDH that shifted toward disulfides or toward thiols, depending on the extent of oxidative damage.

T-cell subsets in the skin and their role in inflammatory skin disorders

T lymphocytes (T cells) are major players of the adaptive immune response. Naive T cells are primed in the presence of cytokines, leading to polarization into distinct T-cell subsets with specific functions. These subsets are classified based on their T-cell receptor profile, expression of transcription factors, surface cytokine and chemokine receptors, and their cytokine production, which together determine their specific function. This review provides an overview of the various T-cell subsets and their function in several inflammatory skin disorders ranging from allergic inflammation to skin tumors. Moreover, we highlight similarities of T-cell responses across different skin disorders, demonstrating the presence of similar and opposing functions for the different T-cell subsets. Finally, we discuss the effects of currently available and promising therapeutic approaches to harness T cells in inflammatory skin diseases for which efficacy next to unwanted side effects provide new insights into the pathophysiology of skin disorders.

A Case of New-Onset Lichen Planus after COVID-19 Vaccination

The COVID 19 vaccination campaign has been underway for about a year now, and there are now many skin reactions associated with the administration of these vaccines in the literature. In view of the forthcoming third dose, we believe it is important to report our experience.

Lichen Planus

Lichen planus (LP) is a T cell-mediated disease affecting the stratified squamous epithelia of the skin and/or mucus membrane. Histologically, the disease is characterized by a lichenoid inflammatory infiltrate and vacuolar degeneration of the basal layer of the epidermis. LP has three major subtypes: Cutaneous, mucosal and appendageal LP. Rarely, it may affect the nails in the absence of skin and/or mucosal changes. LP may also be induced by several drugs, typically anti-hypertensive medication or be associated with infections, particularly viral hepatitis. The diagnosis is based on the clinical presentation and characteristic histological findings. Although the disease is often self-limiting, the intractable pruritus and painful mucosal erosions result in significant morbidity. The current first-line treatment are topical and/or systemic corticosteroids. In addition, immunosuppressants may be used as corticosteroid-sparing agents. These, however are often not sufficient to control disease. Janus kinase inhibitors and biologics (anti-IL-12/23, anti-IL17) have emerged as novel future treatment options. Thus, one may expect a dramatic change of the treatment landscape of LP in the near future.

Evaluation of the Altered Tissue Expression of HSP60 and HSP70 Genes in Oral and Cutaneous Lichen Planus Compared to Normal Healthy Tissues

Background:

Recent highlights have investigated the possible roles of molecular chaperons like heat shock proteins (HSPs) into Lichen Planus (LP)-onset and pathogenesis. This study for the first, determine the expression of both HSP60 and HSP70 genes in cutaneous LP (CLP) and oral LP (OLP) lesions compared to normal healthy cases and between different subtypes of OLP lesions by real-time (RT)-PCR.

Materials and Methods:

Paraffin blocks of LP lesions including 56 OLP and 56 CLP samples were selected from theMashhad University of Medical sciences, Mashhad, Iran. Also 56 biopsy samples of healthy normal participants were selected. The demographic and clinical characteristics were extracted from their medical records. The expression of HSP60 and HPS70 genes were evaluated using the real-time RT-PCR method.

Results:

The comparison of the expression of HSP60 and HSP70 genes among the patients with CLP and OLP showed a significant overexpression of HSP60 and HSP70 genes in both groups compared to the normal participants (P = 0.001). The expression of HSP60 and HSP70 genes was high in both the groups of CLP and OLP patients, but the amount was not significantly different between the two groups. Comparing the two mucosal subgroups of OLP lesions (non-erosive and erosive) showed that the expression of the HSP60 and HSP70 in erosive subtypes of OLP was significantly higher than the non-erosive subtypes of OLP (P = 0.001).

Conclusion:

Regarding the overexpression of HSP60 and HSP70 in the LP lesions compared to healthy biopsies, we conclude that HSP60 and HSP70 could have key roles in the etiopathogenesis of the OLP and CLP lesions. The overexpression of both HSP60 and HSP70 in the erosive OLP group compared to the non-erosive OLP group emphasized the possible roles of HSPs in the pathogenesis and premalignant changes of OLP lesions.

Cluster analysis of circulating plasma biomarkers in prurigo nodularis reveals a distinct systemic inflammatory signature in African Americans

Patients with prurigo nodularis (PN) suffer from intractable itch and dramatic reduction in quality of life. While there is significant clinical heterogeneity in the presentation of PN, disease endotypes remain unknown. We assayed circulating plasma cytokine concentrations in PN patients (n=20) along with matched healthy controls and utilized an unsupervised machine learning algorithm to identify disease endotypes. We found two distinct clusters of PN patients with non-inflammatory (Cluster 1) and inflammatory (Cluster 2) plasma profiles. Cluster 2 had more African-Americans (82%, n=9 vs. 33%, n=3; P=0.028), higher worst-itch numeric rating scale scores (9.5±0.9 vs. 8.3±1.2; P=0.036), and lower quality of life as reflected by higher Dermatology Life Quality Index scores (21.9±6.4 vs. 13.0±4.1; P=0.015). In addition, Cluster 1 had a higher rate of myelopathy (67%, n=6 vs. 18%, n=2; P=0.028). Compared to Cluster 1, Cluster 2 had higher levels of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17A, IL-22, IL-25, and IFN-α. With population-level analysis, African-American PN patients had higher erythrocyte sedimentation rate, C-reactive protein, ferritin, eosinophils, and lower transferrin than Caucasian PN patients. These findings indicate discrete clusters of PN patients with plasma biomarker profiles corresponding to distinct demographic and clinical characteristics, potentially allowing for precision medicine approaches to treat PN.

Epigallocatechin-3-gallate exhibits anti-inflammatory effects in a human interface dermatitis model-implications for therapy

BACKGROUND

Epigallocatechin-3-gallate (EGCG) has been proven effective in treating viral warts. Since anticarcinogenic as well as anti-inflammatory properties are ascribed to the substance, its use has been evaluated in the context of different dermatoses. The effect of EGCG on interface dermatitis (ID), however, has not yet been explored.

OBJECTIVES

In this study, we investigated the effect of EGCG on an epidermal human in vitro model of ID.

METHODS

Via immunohistochemistry, lesional skin of lichen planus patients and healthy skin were analysed concerning the intensity of interferon-associated mediators, CXCL10 and MxA. Epidermal equivalents were stained analogously upon ID-like stimulation and EGCG treatment. Monolayer keratinocytes were treated likewise and supernatants were analysed via ELISA while cells were processed for vitality assay or transcriptomic analysis.

RESULTS

CXCL10 and MxA are strongly expressed in lichen planus lesions and induced in keratinocytes upon ID-like stimulation. EGCG reduces CXCL10 and MxA staining intensity in epidermis equivalents and CXCL10 secretion by keratinocytes upon stimulation. It furthermore minimizes the cytotoxic effect of the stimulus and downregulates a magnitude of typical pro-inflammatory cytokines that are crucial for the perpetuation of ID.

CONCLUSIONS

We provide evidence concerning anti-inflammatory effects of EGCG within a human in vitro model of ID. The capacity to suppress mediators that are centrally involved in disease perpetuation suggests EGCG as a potential topical therapeutic in lichen planus and other autoimmune skin diseases associated with ID.