Involucrin in the differential diagnosis between linear psoriasis and inflammatory linear verrucous epidermal nevus: a report of one case

Adult-onset inflammatory linear verrucous epidermal nevus: Immunohistochemical studies and review of the literature

Adult-onset inflammatory linear verrucous epidermal nevus (ILVEN) is an uncommon cutaneous disease compared to childhood-onset ILVEN. The typical histopathologic features are alternating parakeratosis and orthokeratosis with an absent granular layer underneath parakeratosis, in contrast to a thickened granular layer below the foci of orthokeratosis in psoriasiform epidermal hyperplasia. Herein, we present a 49-year-old woman with typical clinical and histopathologic characteristics of adult-onset ILVEN, including linear arrangement of thick scaly papules and plaques localized on the medial side of her right leg, ankle, and foot. Immunohistochemical studies included involucrin, Ki-67, and keratin-10. Compared to the staining pattern in psoriasis, the expression of involucrin in this case was of lower intensity and localized to upper epidermal layers with relatively less extensive staining beneath regions of parakeratosis as compared to orthokeratosis; Ki-67 showed lower basal layer proliferative activity; and keratin-10 showed a greater intensity of staining within suprabasal epidermis.

Epidermal keratin 5 expression and distribution is under dermal influence

Human skin melanin pigmentation is regulated by systemic and local factors. According to the type of melanin produced by melanocytes, the transfer and degradation of melanosomes differ, thus accounting for most variations between ethnicities. We made the surprising observation that in a drastically changed environment, white and black phenotypes are reversible since Caucasian skin grafted onto nude mice can become black with all black phenotypic characteristics. Black xenografts differed essentially from other grafts by the levels of epidermal FGF-2 and keratin 5. In vitro analysis confirmed that FGF-2 directly regulates keratin 5. Interestingly, this phenomenon may be involved in human pathology. Keratin 5 mutations in Dowling-Degos Disease (DDD) have already been associated with the pheomelanosome-eumelanosome transition. In a DDD patient, keratin 5 was expressed in the basal and spinous layers, as observed in black xenografts. Furthermore, in a common age-related hyperpigmentation disorder like senile lentigo (SL), keratin 5 distribution is also altered. In conclusion, modulation of keratin 5 expression and distribution either due to mutations or factors may account for the development of pigmentary disorders.

Datura Metel L. Ameliorates Imiquimod-Induced Psoriasis-Like Dermatitis and Inhibits Inflammatory Cytokines Production through TLR7/8-MyD88-NF-κB-NLRP3 Inflammasome Pathway

Background: Psoriasis is a chronic, immune-mediated inflammatory skin disease, and the inflammatory response plays an important role in its development and progression. Datura metel L. is a traditional Chinese medicine that exhibited a significant therapeutic effect on psoriasis in our previous study due to its remarkable anti-inflammatory effect. Meanwhile, the mechanism underlying its effects on psoriasis is still unclear. Methods: An imiquimod-induced psoriasis-like dermatitis mouse model was constructed to evaluate the protective effect of the effective part of Datura metel L. (EPD), which was verified by evaluations of the Psoriasis Area and Severity Index (PASI) score. Hematoxylin and eosin (H&E) staining, immunohistochemical examination, enzyme-linked immunosorbent assay (ELISA), and Western blot were used to measure the inflammatory cytokines and the protein expression associated with the Toll-like receptor 7– myeloid differentiation primary response gene 88–nuclear Factor-κB–nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (TLR7/8–MyD88–NF-κB–NLRP3) inflammasome pathway. Results: EPD significantly decreased the PASI, reduced epidermal thickness, and decreased the proliferation and differentiation of epidermal cells in psoriasis-like dermatitis C57BL/6 mice induced by imiquimod (IMQ). Furthermore, EPD reduced the infiltration of CD3+ cells to psoriatic lesions, as well as ameliorated the elevations of intercellular adhesion molecule 1 (ICAM-1) and inhibited the production of imiquimod-induced inflammatory cytokines, including IL-1β, IL-2, IL-6, IL-10, IL-12, IL-17, IL-22, IL-23, tumor necrosis factor-α (TNF-α), monocyte chemotactic protein 1 (MCP-1), and interferon-γ (IFN-γ). Besides, EPD decreased the imiquimod-induced expression levels of TLR7, TLR8, TRAF6, MyD88, p-IKKα, p-IKBα, p-NF-κB, NLRP3, apoptosis-associated speck-like protein contained a caspase recruitment domain (ASC), cysteinyl aspartate specific proteinase 1 (caspase-1), and IL-1β. Conclusion: This study demonstrated that EPD exhibited a protective effect on an imiquimod-induced psoriasis mice model by inhibiting the inflammatory response, which might be ascribed to the inhibition of the TLR7/8–MyD88–NF-κb–NLRP3 inflammasome pathway.

Clinical and Therapeutic Aspects of Linear Psoriasis: A Study of 30 Cases

BACKGROUND

Psoriasis affects 2-4% of the population, with the most common clinical type being plaque psoriasis. The linear form of psoriasis is very rare. The literature on linear psoriasis (LP) consists of only case reports, and data are few.

OBJECTIVE

This study aimed to better understand LP in a large-scale study.

PATIENTS AND METHODS

We retrospectively retrieved the medical records from 14 French medical centers of patients newly diagnosed clinically with LP, with or without the support of histology, between 1 February and 31 July 2015. For each case, we assessed the clinical features, treatments and treatment efficacy.

RESULTS

In total, 30 cases of LP (mean age 26.8 years, 13 males) were reported. Mean age at onset of LP was 20.0 years, with 18 developing LP in childhood. Ten patients had a family history of psoriasis, and two had psoriatic arthritis. A total of 19 cases were linear at onset, with concomitant classical psoriasis; these were termed "superimposed" LP. The remaining 11 cases were not associated with classical psoriasis and were termed "isolated" LP. In four of the superimposed cases, LP developed when the patient was receiving systemic treatment: methotrexate (n = 2), etanercept (n = 1) or infliximab (n = 1). Topical steroids were effective in 76% of cases in which they were used, and systemic treatment was effective in < 66%. Treatments were less effective in LP than in classical psoriasis.

DISCUSSION

We identified a wide range of LP, with two profiles: isolated LP and superimposed LP. Topical treatment usually evoked clinical response, with relative resistance to systemic therapy. Methotrexate and anti-tumor necrosis factor (TNF)-α therapies can possibly unmask LP.

Successful Treatment of Inflammatory Linear Verrucous Epidermal Nevus with Concomitant Psoriasis Using Etanercept

Linear psoriasis is a rare form of the disease characterized by the linear distribution of lesions involving dermatome or along Blaschko's lines. Clinically, it may resemble inflammatory linear verrucous epidermal nevus; a combination of history, skin examination, and histopathology are required to ensure correct diagnosis and appropriate therapy. This paper describes a case of a 23-year-old male presenting with unilateral erythematous scaly plaques arranged in a linear path on the left leg. Etanercept was initiated after poor response to adalimumab. Improvement of his psoriasis was noted, with PASI 75 reduction after 24 weeks of treatment. Clinical studies have shown excellent efficacy of etanercept, and our patient well tolerated treatment with etanercept for 52 weeks without any adverse effects.

Is Ki-67, keratin 16, involucrin, and filaggrin immunostaining sufficient to diagnose inflammatory linear verrucous epidermal nevus? A report of eight cases and a comparison with psoriasis vulgaris

Inflammatory linear verrucous epidermal nevus and linear psoriasis are sometimes hard to differentiate clinically and pathologically. Although immunohistochemical expression of keratin 10 (K10), K16, Ki-67, and involucrin may be useful for differentiating both entities, these results have been reported in only a few cases. We collected data from 8 patients with inflammatory linear verrucous epidermal nevus, 11 with psoriasis vulgaris, and 8 healthy controls and evaluated immunohistochemical expression of Ki-67, K16, involucrin, and filaggrin among them. Ki-67 and K16 overexpression was similar in inflammatory linear verrucous epidermal nevus and psoriasis vulgaris compared with normal skin. Although staining for involucrin showed discontinuous expression in parakeratotic regions in 4 inflammatory linear verrucous epidermal nevus cases, it was continuous in the other 4 cases and in all psoriasis vulgaris cases. Filaggrin expression was present in hyperkeratotic regions but scarce in parakeratotic areas in both inflammatory linear verrucous epidermal nevus and psoriasis vulgaris. The immunostaining pattern of Ki-67, K16, involucrin, and filaggrin may be insufficient to discriminate inflammatory linear verrucous epidermal nevus from psoriasis vulgaris.

The Successful Treatment of a Case of Linear Psoriasis with Ixekizumab

Linear psoriasis is an unusual clinical variation of psoriasis that manifests segmentally along the lines of Blaschko. A major differential diagnosis is inflammatory linear verrucous epidermal nevus (ILVEN). The treatment of linear psoriasis is often challenging, with inadequate response to biological agents reported in the literature. We report a case of a 25-year-old African-American female who presented with asymptomatic hyperkeratotic papules along the lines of Blaschko and was subsequently diagnosed with linear psoriasis. After failing conventional treatment regimens, the patient received a trial of ixekizumab with complete resolution of cutaneous lesions reported after 4 months and only 8 doses of the anti-IL-17 biologic agent.