The systemic autoinflammatory disorders for dermatologists. Part 2: disease examples.

The systemic autoinflammatory disorders (SAIDS) or periodic fever syndromes are disorders of innate immunity, which can be inherited or acquired. They are almost all very rare and easily overlooked; typically, patients will have seen multiple specialities prior to diagnosis, so a high level of clinical suspicion is key. It is important to note that these are 'high-value' diagnoses as the majority of these syndromes can be very effectively controlled, dramatically improving quality of life and providing protection against the development of irreversible complications such as AA amyloidosis. In Part 1 of this review, we took an overview of SAIDS and described the common features; in this article, we take a more in-depth look at the better recognized or more dermatologically relevant conditions.

NRF2 Augments Epidermal Antioxidant Defenses and Promotes Atopy.

Atopic dermatitis is a chronic form of allergic contact dermatitis that is closely associated with a compromised epidermal barrier. Immunogenicity of a given electrophilic hapten after penetration of this barrier depends directly on biochemical reactions in the thiol-rich layer in the stratum granulosum. In response to electrophilic hapten, NF-erythroid 2-related factor 2 (NRF2) in keratinocytes efficiently induces the production of antioxidants. In this study, we show that the immunogenicity of a given hapten depends directly on the extent to which it induces antioxidant host defenses within the epidermal tissue. We found that allergic contact dermatitis did not develop in NRF2-deficient mice because of compromise of the epidermal innate immune responses that upregulate IL-1α. We also analyzed epidermal NRF2 in association with congenital disorders with features similar to atopic dermatitis in humans. Epidermal samples from patients with Netherton syndrome and peeling skin syndrome exhibited elevated levels of NRF2 and also elevated levels of its downstream target, small proline-rich protein 2. Taken together, these results suggest that the thiol-mediated biochemical responses in the stratum granulosum provide a critical link between defective epidermal barrier function and the development of atopy. Likewise, our results suggested that NRF2 may have a profound impact on the generation of cutaneous immunological memory.

Diacylglycerol Kinase ζ Regulates Macrophage Responses in Juvenile Arthritis and Cytokine Storm Syndrome Mouse Models.

Dysregulation of monocyte and macrophage responses are often observed in children with systemic juvenile idiopathic arthritis (sJIA) and cytokine storm syndrome (CSS), a potentially fatal complication of chronic rheumatic diseases. Both conditions are associated with activation of TLR signaling in monocyte and macrophage lineage cells, leading to overwhelming inflammatory responses. Despite the importance of TLR engagement in activating proinflammatory macrophages, relatively little is known about activation of intrinsic negative regulatory pathways to attenuate excessive inflammatory responses. In this study, we demonstrate that loss of diacylglycerol (DAG) kinase (Dgk) ζ, an enzyme which converts DAG into phosphatidic acid, limits inflammatory cytokine production in an arthritic mouse model dependent on TLR2 signaling and in a CSS mouse model dependent on TLR9 signaling. In vitro, Dgkζ deficiency results in reduced production of TNF-α, IL-6, and IL-1ß and in limited M1 macrophage polarization. Mechanistically, Dgkζ deficiency decreases STAT1 and STAT3 phosphorylation. Moreover, Dgkζ levels are increased in macrophages derived from mice with CSS or exposed to plasma from sJIA patients with active disease. Our data suggest that Dgkζ induction in arthritic conditions perpetuates systemic inflammatory responses mediated by macrophages and highlight a potential role of Dgkζ-DAG/phosphatidic acid axis as a modulator of inflammatory cytokine production in sJIA and CSS.

NK cell defects in X-linked pigmentary reticulate disorder.

X-linked reticulate pigmentary disorder (XLPDR, Mendelian Inheritance in Man #301220) is a rare syndrome characterized by recurrent infections and sterile multiorgan inflammation. The syndrome is caused by an intronic mutation in POLA1, the gene encoding the catalytic subunit of DNA polymerase-α (Pol-α), which is responsible for Okazaki fragment synthesis during DNA replication. Reduced POLA1 expression in this condition triggers spontaneous type I interferon expression, which can be linked to the autoinflammatory manifestations of the disease. However, the history of recurrent infections in this syndrome is as yet unexplained. Here we report that patients with XLPDR have reduced NK cell cytotoxic activity and decreased numbers of NK cells, particularly differentiated, stage V, cells (CD3-CD56dim). This phenotype is reminiscent of hypomorphic mutations in MCM4, which encodes a component of the minichromosome maintenance (MCM) helicase complex that is functionally linked to Pol-α during the DNA replication process. We find that POLA1 deficiency leads to MCM4 depletion and that both can impair NK cell natural cytotoxicity and show that this is due to a defect in lytic granule polarization. Altogether, our study provides mechanistic connections between Pol-α and the MCM complex and demonstrates their relevance in NK cell function.

Perifolliculitis capitis abscedens et suffodiens treatment with tumor necrosis factor inhibitors: A case report and review of published cases.

Perifolliculitis capitis abscedens et suffodiens (PCAS) or dissecting cellulitis is a rare condition presenting deep follicular occlusions, follicular ruptures and follicular infections in the scalp area with unknown etiology, which consequently cause primary neutrophilic cicatricial alopecia by the repeated follicular inflammation. PCAS is categorized as one of the "follicular occlusion tetrad" along with hidradenitis suppurativa, acne conglobata and pilonidal cyst. In the pathogenesis of the follicular occlusion tetrad, the involvement of neutrophils and its activator tumor necrosis factor (TNF) have been discussed. Here, we report a case of PCAS that was successfully treated with adalimumab, a human anti-TNF monoclonal antibody. This is the first Asian case of PCAS that was improved by a TNF inhibitor.

Localized unilateral basaloid follicular hamartoma along Blaschko's lines on face.

Basaloid follicular hamartoma (BFH) is a rare hamartoma of hair follicle. Clinical presentations may vary but are united by the same histopathological features in the form of folliculocentric basaloid or squamoid cell proliferation in the superficial dermis, which represents malformed and distorted hair follicles. It is important to recognize this entity as its simulant is basal cell carcinoma, a low-grade malignancy. Here, we report a case of localized unilateral BFH in a Blaschkoid distribution on the face of a 14-year-old female.

Primary cutaneous amyloidosis associated with autoimmune hepatitis-primary biliary cirrhosis overlap syndrome and Sjögren syndrome: A case report.

RATIONALE: Primary cutaneous amyloidosis (PCA) is a localized skin disorder characterized by the abnormal deposition of amyloid in the extracellular matrix of the dermis. The association between PCA and other diseases, although rare, has been documented for various autoimmune diseases. PCA associated with autoimmune hepatitis-primary biliary cirrhosis (AIH-PBC) overlap syndrome and Sjögren syndrome (SS) has not been previously reported in the literature. PATIENT CONCERNS: A 50-year-old woman presented with progressive abnormal liver enzyme levels and was referred to our department. DIAGNOSES: Due to the patient's symptoms, laboratory test results, radiographic findings, and pathologic results, she was diagnosed with PCA associated with AIH-PBC overlap syndrome and SS. INTERVENTIONS: She was subsequently treated with a combination of ursodeoxycholic acid (UDCA), prednisone, and azathioprine. OUTCOMES: While this treatment can achieve therapeutic success, it cannot prevent complications from cirrhosis. This patient remains alive but experienced an emergent gastrointestinal hemorrhage. LESSONS: While we acknowledge that this is a single case, these findings extend our knowledge of immunological diseases associated with PCA and suggest a common, immune-mediated pathogenic pathway between PCA, AIH-PBC overlap syndrome, and SS. After 12 years of follow up, clinical manifestations have developed, and these autoimmune diseases have progressed. The combination of UDCA, prednisone, and azathioprine can achieve therapeutic success but cannot prevent disease progression. Routine follow up for this patient is necessary to document disease progression.

Successful Short Desensitization Treatment Protocol with Narrowband UVB Phototherapy (TL-01) in Polymorphic Light Eruption.

INTRODUCTION: Polymorphic light eruption (PLE) is a common idiopathic photodermatosis that typically presents with pruritic papular or papulovesicular lesions on sun-exposed skin between spring and autumn. In many subjects PLE is mild, and can usually be prevented by the use of broad-spectrum topical sunscreens and a gradual increase in sunlight exposure. However, in some individuals, sunlight exposure results in florid PLE and they often benefit from prophylactic desensitization treatment using phototherapy in early spring, an artificial method that induces a "hardening" phenomenon. OBJECTIVE: To describe and evaluate the efficacy of a short desensitization protocol, based on a one-month-treatment, administered twice a week with narrow band UVB in subjects with severe polymorphic light eruption (PLE). METHODS: A retrospective, open planned and non-randomized study to assess the efficacy of UVB phototherapy in prevention of polymorphic light eruption. RESULTS: Fifteen subjects diagnosed with severe PLE were treated with the standard protocol in our Photobiology Unit between 2014 and 2015. The effect of hardening was sustained during follow up in 87.5% of desensitization treatments. A statistically significant association (p<0.05) between the years of duration of the PLE and the response to treatment was found. CONCLUSIONS: The effect of hardening was maintained in the vast majority of subjects, obtaining a good benefit with no PLE episodes during all the summer. We demonstrate that our standard protocol is effective, and produces a successful outcome for the majority of PLE subjects. Our protocol is shorter than those currently applied, being favourable both for the patient and the physician.

Comparative study of p16 protein expression in squamous cell carcinomas from patients with epidermodysplasia verruciformis and patients without the disease.

Epidermodysplasia verruciformis (EV) is a rare genodermatosis associated with susceptibility to beta-human papilloma virus (HPV) infection. EV patients develop disseminated warts and non-melanoma skin cancer, mainly squamous cell carcinomas (SCC) that are locally aggressive. EV pathogenesis is not yet fully understood, but alterations in the p16 gene play a role in the pathogenesis of neoplasms caused by high-risk genital HPV. To explore its role in EV lesions, we compared p16 expression in SCC from patients with and without EV. Tissue microarray slides composed of 27 SCC from EV patients, and 35 from non-EV patients were stained with an anti-p16 antibody. Twenty (74%) EV tumors exhibited diffuse (nuclear and cytoplasmic) p16 expression, one (4%) displayed focal expression, and six (22%) displayed no p16 staining. Eleven (31%) SCC from non-EV patients presented diffuse p16 staining, 14 (40%) displayed focal expression and 10 (29%) did not express p16. The frequency of diffuse p16 expression was higher in EV tumors than in SCC from patients without EV. The frequency of diffuse p16 expression in moderately and poorly differentiated EV-SCC was similarly higher than non-EV tumors with the same degree of differentiation. The diffuse expression of p16 in EV-SCC suggests that changes in the p16 gene, probably resulting in a functionally defective protein, may be one factor determining the locally aggressive clinical behavior of SCC in young EV patients.

Autoinflammatory Diseases in Pediatric Dermatology-Part 2: Histiocytic, Macrophage Activation, and Vasculitis Syndromes. / Enfermedades autoinflamatorias en dermatología pediátrica. Parte 2: síndromes histiocítico-macrofágicos y síndromes vasculopáticos.

The discovery of new autoinflammatory syndromes and novel mutations has advanced at breakneck speed in recent years. Part 2 of this review focuses on vasculitis syndromes and the group of histiocytic and macrophage activation syndromes. We also include a table showing the mutations associated with these autoinflammatory syndromes and treatment alternatives.

Autoinflammatory Diseases in Pediatric Dermatology-Part 1: Urticaria-like Syndromes, Pustular Syndromes, and Mucocutaneous Ulceration Syndromes. / Enfermedades autoinflamatorias en dermatología pediátrica. Parte 1: síndromes urticariformes, síndromes pustulosos y síndromes con ulceraciones cutáneo-mucosas.

Monogenic autoinflammatory diseases are a heterogeneous emergent group of conditions that are currently under intensive study. We review the etiopathogenesis of these syndromes and their principal manifestations. Our aim is to propose a classification system based on the clinicopathologic features of typical skin lesions for routine clinical use in dermatology. Our focus is on diagnosis in pediatric practice given that this is the period when the signs and symptoms of these syndromes first appear. In Part 1 we discuss the course of urticaria-like syndromes, which include cryopyrin-associated periodic conditions and hereditary periodic fever syndromes. Pustular syndromes are also covered in this part. Finally, we review the range of therapies available as well as the genetic mutations associated with these autoinflammatory diseases.

Co-existing ligneous conjunctivitis and IgG4-related disease.

Herein, we elucidate that ligneous conjunctivitis (LC) was proved as an IgG4-related disease (IgG4-RD) by a series of pathologic studies from primary and recurrent episodes of an LC patient. LC was diagnosed based on clinical presentation and pathological appearance; furthermore, combined with serological examination and immunohistochemical study, the case also conformed to the diagnosis of IgG4-RD. The IgG4-RD, broadly discussed in recent times, is an idiopathic disease entity with tissue fibrosis possibly involving multiple organs. To the best of our knowledge, IgG4-RD has never been reported with LC. By reporting the clinical course and literature review, we should pay attention to the association between these two diseases.

Using an Inbred Horse Breed in a High Density Genome-Wide Scan for Genetic Risk Factors of Insect Bite Hypersensitivity (IBH).

While susceptibility to hypersensitive reactions is a common problem amongst humans and animals alike, the population structure of certain animal species and breeds provides a more advantageous route to better understanding the biology underpinning these conditions. The current study uses Exmoor ponies, a highly inbred breed of horse known to frequently suffer from insect bite hypersensitivity, to identify genomic regions associated with a type I and type IV hypersensitive reaction. A total of 110 cases and 170 controls were genotyped on the 670K Axiom Equine Genotyping Array. Quality control resulted in 452,457 SNPs and 268 individuals being tested for association. Genome-wide association analyses were performed using the GenABEL package in R and resulted in the identification of two regions of interest on Chromosome 8. The first region contained the most significant SNP identified, which was located in an intron of the DCC netrin 1 receptor gene. The second region identified contained multiple top SNPs and encompassed the PIGN, KIAA1468, TNFRSF11A, ZCCHC2, and PHLPP1 genes. Although additional studies will be needed to validate the importance of these regions in horses and the relevance of these regions in other species, the knowledge gained from the current study has the potential to be a step forward in unraveling the complex nature of hypersensitive reactions.