Kazue Yoshida

Application of moisturizer to neonates prevents development of atopic dermatitis

BACKGROUND Recent studies have suggested that epidermal barrier dysfunction contributes to the development of atopic dermatitis (AD) and other allergic diseases. OBJECTIVE We performed a prospective, randomized controlled trial to investigate whether protecting the skin barrier with a moisturizer during the neonatal period prevents development of AD and allergic sensitization. METHODS An emulsion-type moisturizer was applied daily during the first 32 weeks of life to 59 of 118 neonates at high risk for AD (based on having a parent or sibling with AD) who were enrolled in this study. The onset of AD (eczematous symptoms lasting >4 weeks) and eczema (lasting >2 weeks) was assessed by a dermatology specialist on the basis of the modified Hanifin and Rajka criteria. The primary outcome was the cumulative incidence of AD plus eczema (AD/eczema) at week 32 of life. A secondary outcome, allergic sensitization, was evaluated based on serum levels of allergen-specific IgE determined by using a high-sensitivity allergen microarray of diamond-like carbon-coated chips. RESULTS Approximately 32% fewer neonates who received the moisturizer had AD/eczema by week 32 than control subjects (P = .012, log-rank test). We did not show a statistically significant effect of emollient on allergic sensitization based on the level of IgE antibody against egg white at 0.34 kUA/L CAP-FEIA equivalents. However, the sensitization rate was significantly higher in infants who had AD/eczema than in those who did not (odds ratio, 2.86; 95% CI, 1.22-6.73). CONCLUSION Daily application of moisturizer during the first 32 weeks of life reduces the risk of AD/eczema in infants. Allergic sensitization during this time period is associated with the presence of eczematous skin but not with moisturizer use.

Functional tight junction barrier localizes in the second layer of the stratum granulosum of human epidermis

BACKGROUND Mammalian epidermis has two diffusion barriers, the stratum corneum (SC) and tight junctions (TJs). We reported previously that a single living cell layer exists between the SC and TJ-forming keratinocytes in mice; however, the exact location of the TJ barrier in human epidermis has not been defined. OBJECTIVE To investigate the precise distribution of epidermal TJs in relation to various cell-cell junction proteins and the SC and to clarify the barrier function of TJs against macromolecules in human skin. METHODS The localization of various junctional proteins was investigated in human skin sections and in the roofs of bullae formed by ex vivo exfoliative toxin (ET) treatment in three dimensions. ET and single-chain variable fragments (scFv) against desmoglein 1 were used as large diffusion probes. RESULTS Human stratum granulosum (SG) cells have a distinct distribution of TJ, adherens junction, and desmosome proteins in the uppermost three layers (SG1-SG3 from the surface inward). Ex vivo injection of ET or scFv demonstrated that only SG2-SG2 junctions function as a TJ barrier, limiting the inside-out diffusion of these proteins. The roofs of bullae formed by ex vivo ET treatment consisted of SC, SG1 cells, and TJ-forming SG2 cells, probably mimicking bulla formation in bullous impetigo. CONCLUSION Human epidermis has three SG cell layers with distinct properties just beneath the SC, of which only SG2 cells have functional TJs. Our results suggest that human epidermal TJs between SG2 cells form a paracellular diffusion barrier against soluble proteins, including immunoglobulins and bacterial toxins.

Epidermal tight junction barrier function is altered by skin inflammation, but not by filaggrin-deficient stratum corneum

BACKGROUND The tight junction (TJ) barrier is located in the granular layer of the epidermis. Filaggrin deficiency predisposes patients to atopic dermatitis (AD) by impairing stratum corneum (SC) barrier function. Altered TJ barrier function has been observed in the skin of patients with AD; however, it remains unclear whether TJ function is influenced by filaggrin deficiency directly or secondarily via skin inflammation. OBJECTIVE To investigate the in vivo effects of filaggrin deficiency and skin inflammation on epidermal TJ function. METHODS Morphological changes in the TJ were investigated in filaggrin knockout mice and mice with hapten-induced dermatitis using en face visualization of epidermal sheets, and functional changes in the TJ were assessed with an in vivo permeation assay using tracers of various sizes. RESULTS In filaggrin knockout mice, there was no apparent change in the honeycomb morphology of the TJ, TJ component mRNA expression, or TJ barrier function in neonates and adults, indicating that filaggrin-deficiency had no direct effects on the TJ. By contrast, in mice with hapten-induced dermatitis, the mRNA expression of TJ components was decreased markedly and the TJ barrier function was size-dependently impaired: the TJ leaked small tracers (<5 kDa), but not large tracers (>30 kDa). CONCLUSION Filaggrin deficiency did not affect the epidermal TJ barrier directly, but once dermatitis occurred, the skin inflammation induced TJ dysfunction. Since TJ dysfunction induces the SC barrier impairment, skin inflammation will enhance skin permeability to external antigens and result in a vicious cycle of barrier dysfunction and skin inflammation.

Ectopic expression of epidermal antigens renders the lung a target organ in paraneoplastic pemphigus.

Paraneoplastic pemphigus (PNP) is an autoimmune disease of the skin and mucous membranes that can involve fatal lung complications. IgG autoantibodies target the cell adhesion molecules desmoglein (Dsg)3 and plakins, but the nature and targets of infiltrating T cells are poorly characterized. Moreover, the lung involvement in this skin Ag-specific autoimmune condition represents a paradox. To mimic autoimmunity in PNP, we grafted wild-type skin onto Dsg3−/− mice, which resulted in graft rejection and generation of anti-Dsg3 IgG and Dsg3-specific T cells. Transfer of splenocytes from these mice into Rag2−/− mice induced a combination of suprabasilar acantholysis and interface dermatitis, a histology unique to PNP. Furthermore, the recipient mice showed prominent bronchial inflammation of CD4+ and CD8+ T cells with high mortality. Intriguingly, ectopic Dsg3 expression was observed in the lungs of PNP mice, mirroring the observation that squamous metaplasia is often found in the lungs of PNP patients. Dsg3 and other epidermal Ags were ectopically expressed in the lungs after pulmonary injuries by naphthalene, which was sufficient for recruitment of Dsg3-specific CD4+ T cells. These findings demonstrate that squamous metaplasia after pulmonary epithelial injury may play a crucial role in redirecting the skin-specific autoimmune reaction to the lungs in PNP.

Immune response towards the amino-terminus of desmoglein 1 prevails across different activity stages in nonendemic pemphigus foliaceus.

Background  Pemphigus foliaceus (PF) is a blistering skin disease mediated by antibodies to desmoglein (Dsg) 1. The two major subtypes are nonendemic and endemic PF. A previous study in endemic PF demonstrated that changes in antibody epitope could modulate disease relapse and remission.

Novel homozygous mutation, c.400C>T (p.Arg134*), in the PVRL1 gene underlies cleft lip/palate‐ectodermal dysplasia syndrome in an Asian patient

Cleft lip/palate‐ectodermal dysplasia syndrome is a rare, autosomal recessive disorder caused by homozygous loss‐of‐function mutations of the poliovirus receptor‐like 1 (PVRL1) gene encoding nectin‐1. Nectin‐1 is a cell–cell adhesion molecule that is important for the initial step in the formation of adherens junctions and tight junctions; it is expressed in keratinocytes, neurons, and the developing face and palate. Clinical manifestations comprise a unique facial appearance with cleft lip/palate, ectodermal dysplasia, cutaneous syndactyly of the fingers and/or toes, and in some cases, mental retardation. We present the first report, to our knowledge, of an Asian individual with cleft lip/palate‐ectodermal dysplasia syndrome with a novel PVRL1 mutation. A 7‐year‐old Japanese boy, the first child of a consanguineous marriage, showed hypohidrotic ectodermal dysplasia with sparse, brittle, fine, dry hair and hypodontia, the unique facial appearance with cleft lip/palate, cutaneous syndactyly of the fingers and mild mental retardation. Scanning electron microscopic examination of the hair demonstrated pili torti and pili trianguli et canaliculi. Mutation analysis of exon 2 of PVRL1 revealed a novel homozygous nonsense mutation, c.400C>T (p.Arg134*). His parents were heterozygous for the mutant alleles. All four PVRL1 mutations identified in cleft lip/palate‐ectodermal dysplasia syndrome to date, including this study, resulted in truncated proteins that lack the transmembrane domain and intracellular domain of nectin‐1, which is necessary to initiate the cell–cell adhesion process.

Novel heterozygous deletion mutation c.821delC in the AAA domain of BCS1L underlies Björnstad syndrome

Dear Editor, Bj€ ornstad syndrome (BS; Online Mendelian Inheritance in Man [OMIM] #262000) is an autosomal recessive disorder characterized by sensorineural hearing loss and pili torti (twisted hair). It is caused by mutations in BCS1L that encodes a member of the AAA family of ATPases required for the assembly of complex III in the mitochondria. Mutations in BCS1L underlie two other fatal syndromes: mitochondrial complex III deficiency (OMIM #124000) and GRACILE syndrome (OMIM #603358). However, the prevalence of BS in the Japanese population and its molecular basis remain largely unknown. Here, we report a Japanese family with a novel deletion mutation. A 9-year-old girl with sparse hair on her head visited our hospital. Loss of hair had started at 4 months of age. She also had impaired hearing. Her family history was unremarkable for hair and auditory symptoms. The otolaryngologist made a diagnosis of moderate to severe sensorineural deafness by auditory brainstem response testing. Physical examination revealed that her scalp hairs were thin and sparse, with differing lengths. Her eyelashes and eyebrows were also sparse (Fig. 1a,b). There were no remarkable abnormalities of the skin, mucosae, nails or teeth. The serum level of gonadotropin was normal. Light and scanning electron microscopy of her hair demonstrated classical findings of pili torti, with hair shafts being flattened at irregular intervals and twisted 180° from the normal axis (Fig. 1c,d). Based on these findings, the clinical diagnosis was determined as BS. We subsequently sequenced BCS1L, and found that the patient carried two distinct heterozygous mutations in this gene. Of these, one was a deletion mutation c.821delC in exon 7, which was predicted to cause a frame-shift and a premature termination codon at the protein level (p.Pro274Argfs*26) (Fig. 1e). The other was a missense mutation c.917G>A

Delayed-onset heat intolerance in a Japanese patient with X-linked hypohidrotic ectodermal dysplasia associated with a large deletion involving four genes

tumor with multinodular and infiltrative growth pattern. The tumor was mainly composed of polygonal clear myoepithelial type cells with various degree of cytological atypia and surrounded by abundant homogenous eosinophilic stroma (Fig. 1e,f). Immunohistochemistry revealed positivity for high molecular weight cytokeratin and calponin, a-smooth muscle actin, vimentin and p63 (Fig. 1g–k). The histopathological features were consistent with clear cell type myoepithelial carcinoma. Following the biopsy, positron emission tomography was performed to look for the primary tumor site or possible metastasis (Fig. 1b). No abnormally hypermetabolic lesion was observed in the parotid glands or any other area, except for the right vertex area. The diagnosis of primary cutaneous myoepithelial carcinoma (PCMC) on the scalp was given. She received multiple stages of Mohs surgery and the tumor mass was measured as 35 mm 9 80 mm (Fig. 1c). Interestingly, seemingly normal perilesional scalp had also been proved to be myoepithelial carcinoma on frozen biopsy. During 10 months of follow up, no local recurrence was observed (Fig. 1d). Myoepithelial carcinoma is a very rare tumor which accounts for 0.45% of the salivary gland tumors. Frost et al. reported that myoepithelial carcinoma occurred with a female predominance and the mean age at diagnosis was 43 years. It usually manifested as a painless mass on the parotid glands, but it has also been reported to occur in the breast, soft tissue, skin and lung. Histopathological features exhibit both epithelial and myoid phenotypes with various morphological and cytological diversity. Based on the multinodular and infiltrative growth pattern, mixed groups of spindle, plasmacytoid, epithelioid and clear cells with myxoid stroma are observed. The histological appearance of myoepithelial carcinoma may be similar to that of epithelial myoepithelial carcinoma, adenoid cystic carcinoma, proximal type epithelioid sarcoma. Immunohistochemical study would be helpful for the diagnosis. Myoepithelial carcinoma shows an immunoreactivity for both epithelial (pancytokeratin, epithelial membrane antigen) and myogenic (calponin, p63) markers. Myoepithelial carcinoma behaves aggressively with reported rates of local recurrence and metastasis ranging 11–80%. To our knowledge, 11 cases of PCMC have been reported around the world and a few cases have presented on the scalp. In practice, scalp nodules are often regarded as adnexal benign tumors. Considering the poor prognosis of myoepithelial carcinoma, it is essential to establish an early diagnosis. Yet, the possible manifestation of PCMC on the scalp urges clinicians to suspect and further examine scalp nodules. In addition, considering its atypical cutaneous manifestations, a highly meticulous multistage Mohs surgery is necessary to properly manage myoepithelial carcinoma. The resulting large postsurgical defect often causes a challenge for physicians.

Linear keratinocytic epidermal nevi on trunk skin caused by a somatic FGFR2 p.C382R mutation

Dear Editor, Non-epidermolytic keratinocytic epidermal nevi (KEN) are caused by somatic mutations in genes associated with the RAS/mitogen-activated protein kinase (MAPK) pathway or phosphoinositide-3 kinase/AKT pathway. Several particular mutations of KRAS have been reported to cause sebaceous nevi on the face and scalp but KEN on the trunk. A 3-year-old girl exhibited brown papules on her right lower extremity at birth and later developed pebbly brownish plaques scattered along the lines of Blaschko in two regions: one distributed from the right axilla to the right side of the trunk and the other from the right groin to the right thigh (Fig. 1a,b). Several yellowish smooth papules were evident on the right ring and little fingers (Fig. 1c). No extracutaneous sign was evident. Biopsy of the right axillary lesion revealed marked papillomatous acanthosis with rete ridge elongation but without hyperkeratosis or granular degeneration (Fig. 1d,e). Examination of multiple step sections revealed that the lesions contained several small pseudohorn cysts within the epidermis but lacked immature follicles, sebaceous glands and large keratinous cysts (Fig. 1d,e). We obtained written informed consent from her parents according to the guidelines of the institutional review board of the Keio University School of Medicine, and performed nextgeneration sequencing using custom targeted exome sequencing panels of the HaloPlex Target Enrichment System (Agilent Technologies, Santa Clara, CA, USA) for genodermatoses. The target resequencing library was constructed from genomic DNA of the lesional epidermis separated from dermis via ex vivo dispase treatment of biopsied specimen. We identified a missense mutation in FGFR2 (NM_000141.4: c.1144T>C [p.C382R]) and several common variations in genes associated with KEN (Table S1). Sanger sequencing confirmed that the FGFR2 c.1144T>C mutation was present in the lesional epidermis but not in blood leukocytes (Fig. 1f); the other genetic variations were evident in both tissues (Table S1). Therefore, we diagnosed unilateral KEN caused by a somatic FGFR2 p.C382R mutation. The FGFR2 p.C382R mutation, which is suspected as an activating mutation, has been reported in papillomatous, pedunculated sebaceous nevi on the face and the scalp in two cases. Our case showed a partly resembling clinicopathological appearance, namely a pebbly appearance and a lack of hyperkeratosis, but lacked sebaceous differentiation. Such phenotypic differences associated with identical mutations at different body sites have also been reported in KRAS p.G12C and p.G12D mutations, which cause sebaceous nevi on the head but KEN on the trunk. Our case and previous cases suggest that FGFR2 p.C382R mutation triggers the development of sebaceous nevi on the head but KEN on the trunk, while another FGFR2 mutation of p.Y376C causes KEN both on the head and trunk (Table S2). Congenital FGFR2 p.Y376C

Japanese case of xeroderma pigmentosum complementation group C with a novel mutation

Dear Editor, A 1-year-old boy was referred to Kobe University Hospital requesting a possible diagnosis of xeroderma pigmentosum (XP). He had had freckle-like pigmentation on his face since he was a baby. At 9 months, his mother took him to the hospital because the number of freckles had been increasing. Since then, sunlight had been he avoided, his parents applied sunscreen and he seldom spent time outdoors during the day. At presentation, he manifested many freckle-like pigmented maculae on his face and the back of his hands (Fig. 1a). He had never experienced exaggerated sunburn reactions such as blister formation or prolonged erythema upon minimum sun exposure. Skin cancer, mental retardation and neurological symptoms were not observed. His family did not have similar symptoms, and his parents were not consanguineous. A genetic complementation test was carried out by means of host-cell reactivation assay using fibroblasts derived from the patient. Luciferase activity was increased specifically when XPC cDNA was transfected into the patient’s cells, which suggested that the patient belonged to XP complementation group C (XP-C). Genome sequence analysis indicated that the patient harbored a compound heterozygous mutation of c.1024_1025insG and c.1950C>T, resulting in p.D342GfsX32 and p.R579X in XPC (Fig. 1b). Based on these findings, the patient was diagnosed as XP-C. We also confirmed the expression of XPC protein by western blot