Secukinumab in adult patients with lichen planus: efficacy and safety results from the randomized placebo-controlled proof-of-concept PRELUDE study

BACKGROUND

Patients with lichen planus (LP) refractory to available therapies often experience a high disease burden, representing a population with a clear unmet need for new treatments.

OBJECTIVES

To evaluate the efficacy and safety of secukinumab 300 mg over 32 weeks in adult patients with biopsy-proven cutaneous LP (CLP), mucosal LP (MLP) or lichen planopilaris (LPP) that is inadequately controlled by topical corticosteroids.

METHODS

PRELUDE was a randomized double-blind placebo-controlled phase II proof-of-concept study that enrolled patients with CLP, MLP or LPP. Eligible patients were randomized to either secukinumab 300 mg every 4 weeks for 32 weeks (SECQ4W) or placebo for 16 weeks followed by secukinumab 300 mg every 2 weeks (SECQ2W) for 16 weeks. The primary endpoint was achievement of the newly designed Investigator's Global Assessment (IGA) score ≤ 2 at week 16.

RESULTS

Overall, 111 patients were randomized (n = 37 each) to CLP, MLP and LPP cohorts. As the proof-of-concept criteria were not met for any of the three cohorts, the primary objective was not met. A numerically higher proportion of patients achieved IGA ≤ 2 response at week 16 with SECQ4W vs. placebo in the MLP {37.5% [95% credibility interval (Crl) 20.3-57.2] vs. 23.1% (95% Crl 6.5-49.2)} and LPP cohorts [37.5% (95% Crl 20.2-57.3) vs. 30.8% (95% Crl 10.8-57.6)]. In the LPP cohort, a sustained response for IGA ≤ 2 from week 16 to week 32 was achieved with SECQ4W (week 16, 37.5%; week 32, 45.8%), and a substantial improvement was observed in IGA ≤ 2 response in patients from this cohort who switched from placebo (week 16, 30.8%) to SECQ2W after week 16 (week 32, 63.6%). The safety profile was consistent with the known profile of secukinumab and showed no new or unexpected signals.

CONCLUSIONS

PRELUDE is the first randomized controlled basket trial evaluating interleukin (IL)-17A inhibition with secukinumab across three subtypes of LP. Secukinumab was well tolerated and safe, showing different response rates across the three subtypes, with numerical IGA improvements in MLP and LPP, and no response in CLP. The study raises the question of a differential role of IL-17A across LP subtypes. The novel IGA score showed significant correlation with both patient- and physician-reported outcome measurements.

Tissue-resident memory T cells in lichen planus on a surgical scar

This case report for the first time, to the best of our knowledge, shows the significance of CD8+ tissue-resident memory T cells in lichen planus, which occurred on an old scar.

IL-17 family cytokines in inflammatory or autoimmune skin diseases

As potent pro-inflammatory mediators, IL-17 family cytokines play crucial roles in the pathogenesis of various inflammatory and autoimmune skin disorders. Although substantial progress has been achieved in understanding the pivotal role of IL-17A signaling in psoriasis, leading to the development of highly effective biologics, the functions of other IL-17 family members in inflammatory or autoimmune skin diseases remain less explored. In this review, we provide a comprehensive overview of IL-17 family cytokines and their receptors, with a particular focus on the recent advancements in identifying cellular sources, receptors and signaling pathways regulated by these cytokines. At the end, we discuss how the aberrant functions of IL-17 family cytokines contribute to the pathogenesis of diverse inflammatory or autoimmune skin diseases.

CD8+ tissue-resident memory T cells induce oral lichen planus erosion via cytokine network

CD8+ tissue-resident memory T (CD8+ Trm) cells play key roles in many immune-inflammation-related diseases. However, their characteristics in the pathological process of oral lichen planus (OLP) remains unclear. Therefore, we investigated the function of CD8+ Trm cells in the process of OLP. By using single-cell RNA sequencing profiling and spatial transcriptomics, we revealed that CD8+ Trm cells were predominantly located in the lamina propria adjacent to the basement membrane and were significantly increased in patients with erosive oral lichen planus (EOLP) compared to those with non-erosive oral lichen planus (NEOLP). Furthermore, these cells displayed enhanced cytokine production, including IFN-γ (Interferon-gamma, a pro-inflammatory signaling molecule), TNF-α (Tumor Necrosis Factor-alpha, a cytokine regulating inflammation), and IL-17 (Interleukin-17, a cytokine involved in immune response modulation), in patients with EOLP. And our clinical cohort of 1-year follow-up was also supported the above results in RNA level and protein level. In conclusion, our study provided a novel molecular mechanism for triggering OLP erosion by CD8+ Trm cells to secrete multiple cytokines, and new insight into the pathological development of OLP.

The potential roles of Th17 cells in the pathogenesis of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated chronic autoimmune disease, whose pathogenesis and etiology are not entirely understood. OLP is characterized by subepithelial lymphocyte infiltration and elevated intra-epithelial lymphocytes. The majority of lamina propria lymphocytes are CD4⁺ T cells. CD4⁺ helper T (Th) cells play a crucial role in activating CD8⁺ cytotoxic T cells (CTLs) through interactions and cytokine production. Th1 and Th2 cells are well-accepted to be associated with OLP pathogenesis. However, OLP treatment is challenging yet, the more information we have about the pathology of OLP, the easier it will be treated. With the discovery of Th17 cells in recent years and the demonstration of their role in autoimmune disease, many researchers started to investigate the role of Th17 in the pathogenesis of OLP.

METHODS

To make up this review, studies covering the role of TH17 in different types of lichen planus were selected from major databases.

RESULTS

As we review in this article, Th17 cells and their signature cytokines play an important role in OLP pathogenesis. As well, utilizing some anti-IL-17 antibodies showed promising results in improving the disease; however, more studies are still needed to better understand and treat OLP.

Serum and salivary cytokines in patients with oral lichen planus treated with Photobiomodulation

OBJECTIVES

To evaluate the serum and salivary levels of IL-1β, IL-6, IL-17A, TNF-α, IL-4, and IL-10 in patients with oral lichen planus (OLP) treated with Photobiomodulation (PBM) and clobetasol propionate 0.05%.

MATERIAL AND METHODS

Thirty-four OLP patients were randomized into two groups: Control (clobetasol propionate 0.05%) and PBM (660 nm, 100 mW, 177 J/cm2 , 5 s, 0.5 J per point). Serum and saliva were collected at baseline and at the end of treatment (after 30 days) and evaluated using ELISA. The cytokine results were correlated with pain, clinical subtypes, and clinical scores of OLP.

RESULTS

IL-1β, IL-6, IL-17A, TNF-α, and IL-4 levels were higher in saliva in relation to serum. IL-1β was the most concentrated cytokine in saliva, and a positive correlation with the severity of OLP was noticed. After treatment with corticosteroid, IL-1β in saliva decreased significantly. No modulation of all cytokines was observed after PBM.

CONCLUSION

IL-1β appears to be an important cytokine involved in OLP pathogenesis. In addition, the mechanisms of action of PBM do not seem to be linked to the modulation of pro or anti-inflammatory cytokines at the end of treatment. It is possible that this events occurred early during treatment.

IL-17 Expression in the Perifollicular Fibrosis in Biopsies From Lichen Planopilaris

BACKGROUND

Lichen planopilaris (LPP) is a primary lymphocytic cicatricial alopecia for which therapy is often ineffective and there is no cure.

OBJECTIVES

Looking for a new targetable molecule in the treatment of LPP, we sought to verify whether IL-17 expression is increased in scalp biopsies from patients with active scalp lesions of LPP.

METHODS

Horizontal sections of hematoxylin and eosin-stained slides from 40 scalp biopsies of active LPP were retrospectively collected and stained with the monoclonal antibody against IL-17 (Abcam, Cambridge, MA; ab79056, dilution 1:100). Twenty biopsies from patients with chronic telogen effluvium served as controls because of their morphological resemblance to the normal scalp. Statistical analysis was performed using IBM SPSS Statistics for Windows (IBM Corporation, Armonk, NY).

RESULTS

The main finding was the positive cytoplasmic expression of IL-17 in the perifollicular fibrosis of the affected follicles in LPP which was statistically significant compared with the controls ( P < 0.0001). The labeled cells were identified as fibroblasts based on their spindle shape and fascicular concentric arrangement in tight perifollicular distribution. Although most of the LPP specimens (n = 35; 87.5%) also revealed cytoplasmic IL-17 expression in the lichenoid inflammatory infiltrate, the results were not statistically significant ( P = 0.1351).

CONCLUSION

Our immunohistochemistry results show that blocking the IL-17 inflammatory pathway may interfere with the progression of the perifollicular fibrosis and inflammation in LPP.

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

Cutaneous lichen planus (CLP) and psoriasis (PSO) are both common chronic inflammatory skin diseases for which development of new treatments requires the identification of key targets. While PSO is a typical Th17/IL-17-disorder, there is some evidence that Th1/IFN-ɣ dominate the inflammatory process in CLP. Nonetheless, the immunopathogenesis of CLP is not fully explained and key immunological factors still have to be recognized. In this study, we compared the immune signature of CLP lesions with the well-characterized inflammation present in PSO skin. First, we analysed the histological and immunohistological characteristics of CLP and PSO. Second, we assessed the cytokine expression (IL1A, IL1B, IL4, IL6, IL8, IL10, IL17A, IL19, IL21, IL22, IL23A, IL13, IFNG, TNF, IL12A, IL12B and IL36G) of lesional skin of CLP with PSO by qPCR. Histology revealed a similar epidermal thickness in CLP and PSO. Immunohistochemically, both diseases presented with an inflammatory infiltrate mainly composed by CD3⁺ CD4⁺ T cells rather than CD3⁺ CD8⁺ . Importantly, mRNA analysis showed a distinct cytokine signature: while levels of IL12B, IL1A, IL6 and IL23 were similar between the two groups, the characteristic PSO-associated cytokines IL8, IL17A, IL22, IL19 and IL36G were expressed at very low levels in CLP. In contrast, CLP lesional skin was dominated by the expression of IFNG, IL21, IL4, IL12A and TNF. Immunohistochemistry confirmed the dominance of IL-21, IFN-ɣ and also pSTAT1 in the dermal infiltrate of CLP, while IL-17A was more present in PSO. Collectively, this study improves our understanding of the immunological factors dominating CLP. The dominating cytokines and signalling proteins identified suggest that anti-cytokine therapeutics like JAK inhibitors may be beneficial in CLP.

Possible Relation between Vitamin D and Interleukin-17 in the Pathogenesis of Lichen Planus

BACKGROUND

Lichen planus (LP) is a chronic autoimmune inflammatory mucocutaneous disease. Interleukin (IL)-17 is the signature cytokine of T-helper 17 cells, involved in the aetiology of many autoimmune and inflammatory disorders. Vitamin D has an immune-regulatory role and suppresses IL-17 production via direct transcriptional inhibition of IL-17 gene expression.

OBJECTIVE

To explore the relationship of IL-17 and vitamin D levels with LP, and the possible inter-relationship between IL-17 and vitamin D.

METHODS

The study enrolled 30 patients with LP and 30 healthy controls. Blood samples and skin biopsies were taken from all participants for evaluation of serum vitamin D, and serum and tissue IL-17 levels using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Patients had significantly higher serum and tissue IL-17 (p < 0.001 for both), as well as significantly lower serum vitamin D levels and more deficient patterns of vitamin D status than controls (p < 0.001 for both). In the patient group, there was a statistically significant positive correlation between extent of the disease and serum IL-17. There was no direct statistical correlation between IL-17 levels and serum vitamin D in either patients or controls.

CONCLUSION

This study confirms a previously suggested role of IL-17 in the pathogenesis of LP and suggests its relation to the extent and severity of the disease. We also found an association between vitamin D deficiency and LP. However, a direct relationship between IL-17 and vitamin D deficiency could not be clarified.

Increased Serum Level and High Tissue Immunoexpression of Interleukin 17 in Cutaneous Lichen Planus: A Novel Therapeutic Target for Recalcitrant Cases?

Background

Interleukin-17 is supposed to play an important role in the pathogenesis of oral lichen planus (OLP). However, there is scarce data in the literature on its significance in the cutaneous variant of the disease.

Objectives

To determine the serum level and tissue immunoexpression of IL-17 in cutaneous lichen planus (CLP).

Methods

Fifty-two adult patients with CLP, without any significant autoimmune or inflammatory conditions, were included in the first part of the study. The control group consisted of 27 age- and sex-matched healthy volunteers. Serum concentration of IL-17 was quantified using enzyme-linked immunosorbent assay (ELISA) kit. In the second part of the study, the tissue expression of IL-17 was assessed in archival paraffin-embedded biopsy specimens from CLP (n = 14) against normal control tissues (n = 11) using immunohistochemical assays. The expression was evaluated using Zeiss Axio Imager A2 light microscope. Positively stained cells were counted in 10 fields of view for biopsy specimen at 200x magnification, and the mean value was calculated.

Results

The serum level of IL-17 was significantly elevated in patients with CLP, compared with healthy volunteers (0.218 ± 0.221 ng/ml versus 0.126 ± 0.058 ng/ml, respectively; p = 0.025). No correlation was found between the serum concentration of IL-17 and patient age, gender, disease duration, extent of skin involvement, the presence or intensity of pruritus, and coexistence of mucosal lesions. In tissue samples from CLP lesions, significantly higher numbers of cells expressing IL-17 were found when compared to a healthy skin (p < 0.001).

Conclusion

Elevated serum concentration of IL-17 and high expression in a lesional skin support the hypothesis that IL-17 is implicated in the immunopathogenesis of CLP. These findings may constitute a premise for the future use of anti-IL-17 monoclonal antibodies in the treatment of severe and recalcitrant forms of CLP.

Photodynamic therapy in oral lichen planus: A prospective case-controlled pilot study

Oral lichen planus (OLP) is a common, chronic relapsing inflammatory disorder of the mucous membranes, which causes major discomfort. Current treatment includes topical/systemic glucocorticoids, immune modulators and systemic immunosuppressants, which may lead to considerable side-effects. The aim of this study was to determine the clinical and immunological efficacy of photodynamic therapy (PDT) in OLP as an alternative, easy-to-use, safe and non-invasive treatment. Twenty patients with OLP were treated with PDT in a prospective case-controlled pilot-study. PDT was performed on the most extensive oral lesion in 4 sessions (day 1, 3, 7, 14). Peripheral blood and lesional T cells were analysed before (day 1) and after PDT treatment (day 28). PDT led to a statistically significant reduction of clinical parameters (lesion size, ABSIS, Thongprasom-score) and improvement of all evaluated quality-of-life (QOL) items. The clinical improvement was accompanied by a significant decrease of the relative number of CD4+ and CD8+ T cells in mucosal OLP-lesions. Furthermore, CXCL10 plasma levels were decreased and the number of activated peripheral CD4 + CD137+ and CD8 + CD137+ T cells and IL-17-secreting T cells was diminished. PDT treatment in OLP leads to lesion reduction and improvement of QOL, and induces local and systemic anti-inflammatory effects. The study identifies PDT as a novel therapeutic option in OLP.

Emerging Topical and Systemic JAK Inhibitors in Dermatology

Accumulating data on cellular and molecular pathways help to develop novel therapeutic strategies in skin inflammation and autoimmunity. Examples are psoriasis and atopic dermatitis, two clinically and immunologically well-defined disorders. Here, the elucidation of key pathogenic factors such as IL-17A/IL-23 on the one hand and IL-4/IL-13 on the other hand profoundly changed our therapeutic practice. The knowledge on intracellular pathways and governing factors is shifting our attention to new druggable molecules. Multiple cytokine receptors signal through Janus kinases (JAKs) and associated signal transducer and activators of transcription (STATs). Inhibition of JAKs can simultaneously block the function of multiple cytokines. Therefore, JAK inhibitors (JAKi) are emerging as a new class of drugs, which in dermatology can either be used systemically as oral drugs or locally in topical formulations. Inhibition of JAKs has been shown to be effective in various skin disorders. The first oral JAKi have been recently approved for the treatment of rheumatoid arthritis and psoriatic arthritis. Currently, multiple inhibitors of the JAK/STAT pathway are being investigated for skin diseases like alopecia areata, atopic dermatitis, dermatomyositis, graft-versus-host-disease, hidradenitis suppurativa, lichen planus, lupus erythematosus, psoriasis, and vitiligo. Here, we aim to discuss the immunological basis and current stage of development of JAKi in dermatology.

Significant reduction in the expression of interleukins-17A, 22 and 23A, forkhead box p3 and interferon gamma delineates lichen planus pigmentosus from lichen planus

Recent studies have noticed significant role of interleukin (IL)-17, 22, 23, Foxp3, interferon-gamma (IFN-γ) and Wnt5a in oral and cutaneous lichen planus (LP). This study was undertaken to assess whether similar expression exists in lichen planus pigmentosus (LPP). We recruited 30 patients of treatment-naïve 'LPP' (in absence of cutaneous/mucosal LP elsewhere, group 1), 10 patients having active treatment-naïve cutaneous 'LP' (group 2), 10 patients having 'post-LP' hyperpigmentation (in absence of active LP and off treatment for at least past 3 months, group 3), and 10 controls. Quantitative real-time polymerase chain reaction (qRT-PCR, peripheral blood mononuclear cells [PBMCs] and skin) and immunohistochemistry (IHC, skin) was performed. mRNA expression (in PBMCs) of IL-17A, IL-22, IL-23A, IFN-γ and Foxp3 was significantly decreased in group 1 and 3 as compared to group 2 (p < 0.05). Wnt5a expression was maximal in controls; and while there was no difference between group 1 and 2; whereas expression in group 3 was significantly lesser than group 1 and 2 (p < 0.05). qRT-PCR (skin) and IHC (skin) revealed similar results; and mRNA expression and mean fluorescence intensity of IL-17A, IL-22, IL-23A/R was significantly increased in group 2 and 3 compared to group 1 (p < 0.05). Mean fluorescence intensity and mRNA expression of IFN-γ, Foxp3 and Wnt5a were significantly increased in group 2 compared to group 1 (p < 0.05); whereas the difference between group 1 and 3 was not significant. Mean fluorescence intensity and mRNA expression of IL-17A, 1L-22 and IFN-γ showed no difference between group 2 and 3; whereas that of IL-23A/R, foxp3 and wnt5a were significantly higher in group 2 than group 3 (p < 0.05). Overall, maximal expression of IL-17A, IL-22, IL-23A, IFN-γ and Foxp3 (mRNA PBMCs) was observed in LP. Minimal expression of IL-17A, IL-22, IL-23A/R, IFN-γ and Foxp3 (mRNA skin and IHC skin) was seen in LPP patients. In contrast to LP, LPP lacks the expression of IFN-γ, Foxp3 and the cytokines representing Th17 pathway, and thus seems to have a distinct pathogenesis.

Therapeutic Targeting of Th17/Tc17 Cells Leads to Clinical Improvement of Lichen Planus

Lichen planus (LP) is a common, chronic relapsing inflammatory disorder of the skin and mucous membranes which often poses a major therapeutic challenge due to its refractory course. Novel pathogenesis-based therapies are urgently needed. As several studies have shown that IL-17 may contribute to LP pathogenesis, we investigated whether therapeutic targeting of IL-17⁺ T cells leads to clinical improvement of mucosal and cutaneous LP lesions. A total of five patients with lichen planus were treated in a compassionate use trial with either secukinumab (anti-IL-17; 3 patients with acute and chronic recalcitrant muco-cutaneous LP), ustekinumab (anti-IL-12/IL-23; 1 patient with recalcitrant oral LP) or guselkumab (anti-IL-23; 1 patient with recalcitrant oral LP). The clinical course of the patients was assessed by the Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) reflecting both extent and severity of disease and functional sequelae of oral involvement for at least 12 weeks. The inflammatory infiltrate in lesional and post-lesional skin was analyzed by immunohistochemistry before and after treatment. Furthermore, the cytokine profile of peripheral blood T cells from the treated patients was assessed by flow cytometry and/or ELISpot assay. Treatment with secukinumab induced rapid and prolonged clinical amelioration of muco-cutaneous LP. Clinical improvement was accompanied by a strong reduction of the Th1 and Th17/Tc17 cellular mucosal and cutaneous infiltrate. Moreover, long-term treatment of one patient with recalcitrant oral LP with ustekinumab led to healing of the ulcerative oral lesions and a reduction of peripheral blood and lesional IL-17⁺ T cells. Finally, treatment with guselkumab led to a marked clinical improvement in a patient with recalcitrant erosive oral LP. These findings show for the first time that therapeutic targeting of Th17/Tc17 cells leads to a pronounced clinical amelioration of mucosal and cutaneous LP and strongly suggests that IL-17-producing T cells are central to disease pathogenesis. Thus, therapeutic targeting of Th17/Tc17 cells opens new therapeutic avenues in the treatment of recalcitrant LP.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.

Altered expression of interleukin-17A and its targeting microRNAs in oral lichen planus: a pilot study

OBJECTIVE

To investigate the potential role of interleukin (IL)-17A and its targeting microRNAs (miRNAs) in oral lichen planus (OLP).

STUDY DESIGN

We compared the IL-17A expression levels in biopsies from patients with OLP (n = 50) against normal controls (n = 19) by using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analyses, identified the targeting miRNAs of IL-17A, and examined the miRNA expression levels in OLP.

RESULTS

IL-17A expression was significantly increased in patients with OLP compared with controls. The dual-luciferase reporter assay system demonstrated that miR-635 and miR-578 were the target miRNAs of IL-17A in human embryonic kidney 293 cells, which was consistent with predictions from bioinformatics software analyses. In contrast with IL-17A, the expression levels of miR-635 and miR-578 in OLP were significantly decreased compared with controls.

CONCLUSIONS

This pilot study found that low levels of miR-635 and miR-578 expression were associated with high expression of IL-17A, suggesting that IL-17A and its targeting miRNAs contribute to the pathogenesis of OLP.

JAK3 as an Emerging Target for Topical Treatment of Inflammatory Skin Diseases

The recent interest and elucidation of the JAK/STAT signaling pathway created new targets for the treatment of inflammatory skin diseases (ISDs). JAK inhibitors in oral and topical formulations have shown beneficial results in psoriasis and alopecia areata. Patients suffering from other ISDs might also benefit from JAK inhibition. Given the development of specific JAK inhibitors, the expression patterns of JAKs in different ISDs needs to be clarified. We aimed to analyze the expression of JAK/STAT family members in a set of prevalent ISDs: psoriasis, lichen planus (LP), cutaneous lupus erythematosus (CLE), atopic dermatitis (AD), pyoderma gangrenosum (PG) and alopecia areata (AA) versus healthy controls for (p)JAK1, (p)JAK2, (p)JAK3, (p)TYK2, pSTAT1, pSTAT2 and pSTAT3. The epidermis carried in all ISDs, except for CLE, a strong JAK3 signature. The dermal infiltrate showed a more diverse expression pattern. JAK1, JAK2 and JAK3 were significantly overexpressed in PG and AD suggesting the need for pan-JAK inhibitors. In contrast, psoriasis and LP showed only JAK1 and JAK3 upregulation, while AA and CLE were characterized by a single dermal JAK signal (pJAK3 and pJAK1, respectively). This indicates that the latter diseases may benefit from more targeted JAK inhibitors. Our in vitro keratinocyte psoriasis model displayed reversal of the psoriatic JAK profile following tofacitinib treatment. This direct interaction with keratinocytes may decrease the need for deep skin penetration of topical JAK inhibitors in order to exert its effects on dermal immune cells. In conclusion, these results point to the important contribution of the JAK/STAT pathway in several ISDs. Considering the epidermal JAK3 expression levels, great interest should go to the investigation of topical JAK3 inhibitors as therapeutic option of ISDs.

The many faces of interleukin-17 in inflammatory skin diseases

Interleukin (IL)-17 is an emerging target for inflammatory skin disorders. Given the remarkable success of its therapeutic inhibition in psoriasis, the pathogenic role of this cytokine is being explored in other immune-mediated diseases. Interestingly, IL-17 is linked to particular skin conditions where its activation coincides with disease flares. The leading hypothesis for its contribution to proinflammatory signalling cascades is driving inflammasome activation. However, IL-17 stimulation also releases a range of noninflammasome-related cytokines from human skin. Furthermore, a role in cytotoxic responses and an important interplay with the microbiome is hypothesized. While treatment failure would be surprising in neutrophilic dermatoses, the picture might be more complex in lymphocyte-mediated conditions. Nonetheless, increasing insights into the pathogenesis suggest that beneficial responses are also probable in the latter conditions. Study of this pathway in the skin reveals some intriguing aspects of the IL-17-related immunological network.

Immunoexpression of Th17-related cytokines in oral lichen planus

A recently described lineage of lymphocytes, Th17 cells, has been associated with inflammatory and autoimmune diseases. The aim of this article was to assess the immunoexpression of cytokines related to this lineage, interleukin-17 (IL-17) and IL-23 and in reticular and erosive oral lichen planus (OLP). The sample included 41 cases of OLP (23 reticular and 18 erosive) and 10 cases of inflammatory fibrous hyperplasia (IFH). Lymphocytes exhibiting cytoplasmic immunostaining were counted. Epithelial immunostaining was also evaluated. There was no statistical differences in the number of IL-17 and IL-23 lymphocytes between the OLP (55.40 and 48.40, respectively) and IFH (39.30 and 44.40, respectively). A significantly higher number of IL-23 lymphocytes was found in erosive OLP group (63.80) when compared with reticular (41.40) and IFH lesions (44.40) (P=0.019). Furthermore, epithelial immunopositivity for IL-17 and IL-23 was higher in OLP lesions than in IFH (P=0.012 and P=0.011, respectively). A significantly higher number of IL-23 lymphocytes in erosive OLP and the strong epithelial immunopositivity for IL-23 and IL-17 in OLP group could suggest an important participation of TCD4 Th17 response in this disorder.

Oral, esophageal and cutaneous lichen ruber planus controlled with alitretinoin: case report and review of the literature

BACKGROUND

Therapy-resistant lichen planus (LP) can be a challenging condition for dermatologists. There are some case reports about successful treatments with alitretinoin of cutaneous and oral, but not of esophageal LP.

OBJECTIVE

We present the unique case of a patient with cutaneous, oral and esophageal LP which was refractory to classical treatment options (topical clobetasol propionate and pimecrolimus, intramuscular triamcinolone acetonide); because of systemic side effects the patient did not tolerate systemic acitretin dosed up to 25 mg daily.

METHODS

Oral alitretinoin was used at a dose of 30 mg daily.

RESULTS

Both oral and skin changes as well as dysphagia completely resolved within 4 weeks without any severe side effects and the drug was used for 6 months. No papules, intraoral striae or dysphagia recurred during the 6 months of treatment. After 4 months the patient relapsed with mucosal patches so that a second cycle was initiated for 6 months where oral LP lesions resolved after 4 weeks also (with sporadic mild headache).

CONCLUSION

Further studies are needed to better understand the impact of alitretinoin in LP. Our observation suggests alitretinoin as a new, well-tolerated treatment option for esophageal LP after failed response to conventional treatments.

Serum Level of Interleukin 17 in Patients with Erosive and Non erosive Oral Lichen Planus

Background and aims

Oral lichen planus is a relatively common chronic oral mucosal disease of unknown etiology. Regarding numerous studies on the immunologic factors involved in the etiology of lichen planus, the present study evaluated the serum interleukin-17 (IL-17) level in patients with erosive and non-erosive oral lichen planus.

Materials and methods

This descriptive analytical study included 24 patients with erosive oral lichen planus (EOLP), 24 patients with non-erosive oral lichen planus (NEOLP) and 24 healthy volunteered as control. Blood samples of the subjects underwent ELISA, using special kits, to determine serum interleukin-17 levels. Data was analyzed using with descriptive statistic, chi-square test, and one-way ANOVA and Tukey post-hoc test with SPSS 16 software.

Results

EOLP patients showed a high level of serum IL-17 compared with NEOLP patents and control groups (EOLP=184.16 ± 12.41 pg/mL, NEOLP=106.09±10.78 pg/mL, control=15.50 ± 4.34 pg/mL, P - 0.001).

Conclusion

High level of serum IL-17 in erosive oral lichen planus patients compared to the non-erosive type and healthy individuals may be the reason for higher inflammation and atrophy in the erosive type.

Potential pathogenetic role of Th17, Th0, and Th2 cells in erosive and reticular oral lichen planus

OBJECTIVES

The role of Th17 cells and associated cytokines was investigated in oral lichen planus.

MATERIAL AND METHODS

14 consecutive patients with oral lichen planus were investigated. For biological studies, tissues were taken from reticular or erosive lesions and from normal oral mucosa (controls) of the same patient. mRNA expression for IL-17F, IL-17A, MCP-1, IL-13, IL-2, IL-10, IL-1β, RANTES, IL-4, IL-12B, IL-8, IFN-γ, TNF-α, IL-1α, IL-18, TGF-β1, IL-23R, IL-7, IL-15, IL-6, MIG, IP-10, LTB, VEGF, IL-5, IL-27, IL-23A, GAPDH, PPIB, Foxp3, GATA3, and RORC was measured using the QuantiGene 2.0.

RESULTS

Results showed that Th17-type and Th0-type molecules' mRNAs, when compared with results obtained from tissue controls, were increased in biopsies of erosive lesions, whereas Th2-type molecules' mRNAs were increased in reticular lesions. When the CD4+ T-cell clones, derived from oral lichen planus tissues and tissue controls, were analyzed, a higher prevalence of Th17 (confirmed by an increased CD161 expression) and Th0 CD4+ T clones was found in erosive lesions, whereas a prevalence of Th2 clones was observed in reticular lesions.

CONCLUSIONS

Our data suggest that Th17, Th0, and Th2 cells, respectively, may have a role in the pathogenesis of erosive and reticular oral lichen planus.