Nuclear IL-33 Plays an Important Role in the Suppression of FLG, LOR, Keratin 1, and Keratin 10 by IL-4 and IL-13 in Human Keratinocytes.

IL-33 is a chromatin-associated multifunctional cytokine implicated in the pathogenesis of atopic dermatitis (AD), an inflammatory skin disorder characterized by skin barrier dysfunction. The previous reports show that IL-33 is highly detected in the nucleus of epidermal keratinocytes in AD lesions compared with that in unaffected or normal skin. However, it is unclear whether intracellular IL-33 directly contributes to the pathogenesis of AD. T helper type 2 cytokines IL-4 and IL-13 that are elevated in AD lesions suppress keratinocyte differentiation to impair skin barrier function. We investigated whether intracellular IL-33 is involved in IL-4 and IL-13 function. In monolayer culture and living skin equivalent analyses, IL-4 and IL-13 increased the expression of full-length IL-33 in the nucleus of keratinocytes by activating the MAPK/extracellular signal‒regulated kinase kinase/extracellular signal‒regulated kinase signaling pathway, which is necessary for the inhibition of differentiation markers FLG, LOR, keratin 1, and keratin 10. The nuclear IL-33 functions as a transcription cofactor of signal transducer and activator of transcription 3, increasing the binding of phosphorylated signal transducer and activator of transcription 3 to FLG promoter, thereby inhibiting its transcription, and it inhibits the expression of transcription factor RUNX1 by signal transducer and activator of transcription 3 and signal transducer and activator of transcription 6, thereby downregulating LOR, keratin 1, and keratin 10. Thus, the elevated nuclear IL-33 in the epidermis of AD lesions may be involved in the pathogenesis of AD by inhibiting keratinocyte differentiation and skin barrier function.

Bowen Disease With Sebaceous Differentiation: A Case Report and Immunohistochemical Analysis of Adipophilin and Cytokeratin 1.

Bowen disease with sebaceous differentiation has been rarely documented to date. Here, we present a case of Bowen disease with sebaceous differentiation. A 67-year-old man presented with a 6.0 × 3.5 cm erythematous plaque adjacent to a 7.0 × 3.0 cm erythematous plaque on his left abdomen. Dermoscopy revealed yellow structureless areas and dotted vessels on a pink homogenous background in addition to surface scales. Histopathological examination of the upper erythematous plaque showed parakeratosis and acanthosis with proliferation of atypical keratinocytes in the epidermis. Some of the atypical cells had large and hyperchromatic nuclei. Histopathological examination of the lower erythematous plaque showed tumor nests extending from the epidermis. Tumor nests with hyperchromatic and atypical cells had vacuolated cells. The diagnosis of Bowen disease with sebaceous differentiation was made. Immunohistochemistry revealed a positive reaction for cytokeratin 1 (CK1) in tumor cells of Bowen disease and a negative reaction for CK1 in tumor cells with the sebaceous differentiation, whereas immunohistochemistry revealed no apparent adipophilin-positive granules in tumor nests of Bowen disease compared with the prominent staining of adipophilin in tumor nests with sebaceous differentiation. We show Bowen disease with sebaceous differentiation taking advantage of immunohistochemistry of adipophilin and CK1. Those findings of Bowen disease with sebaceous differentiation may deepen our understandings and insights into the pathogenesis of sebaceous carcinoma and Bowen disease.

Proteomic characterization of the acid-insoluble fraction of whole saliva from preterm human newborns.

The acid-insoluble salivary proteome obtained by addition of TFA to whole human saliva from adults, preterm and at-term newborns has been analysed by 2-DE in order to evidence differences among the three groups, and integrate data previously obtained on the acid-soluble fraction. 2-DE spots differentially expressed among the three groups were submitted to in-gel tryptic digestion and the peptide mixtures analysed by high resolution HPLC­ESI­MS/MS. By this strategy, we identified 3 over-expressed proteins in at-term newborns with respect to preterm newborns and adults (BPI fold-containing family A member 1, annexin A1, and keratin type 1 cytoskeletal 13), and several over-expressed proteins in adults (fatty acid-binding protein, S100 A6, S100 A7, S100 A9, prolactin-inducible protein, Ig kappa chain, cystatin SN, cystatin S/SA and α-amylase 1). Four spots, already detected but not characterized by other authors in human saliva 2-DE, were attributed to different protein species of S100 A9 (long-type and long-type monophosphorylated, short-type and short-type monophosphorylated) by MS/MS analysis of tryptic peptides and sequential staining of 2-DE gels with Pro-Q Diamond, for specific detection of phosphoproteins, and total protein SYPRO Ruby stain. SIGNIFICANCE: Differential protein expression analysis of the acid insoluble fraction of saliva from preterm, at-term newborns and adults has been performed in this study by coupling 2-DE analysis and high-resolution tandem mass spectrometry in order to complete the information previously obtained by top-down LC­MS only on the acid-soluble proteome. Several proteins identified in the acid insoluble fraction of both preterm newborn and adult saliva are not of glandular origin, being only prolactin-inducible protein, salivary cystatins, α-amylase and polymeric immunoglobulin receptor exclusive of salivary glands. Three proteins resulted increased in at-term newborns with respect to preterm newborns and adults: BPI fold-containing family A member 1, two proteoforms of annexin A1 and keratin type 1 cytoskeletal 13, while several proteins were significantly increased in adults.

Determination of cytokeratins 1, 13 and 14 in oral lichen planus.

UNLABELLED: INTRODUCCION: Cytokeratins (CK) are molecules of the cytoskeleton that contribute to the cellular differenciation. We studied the expression of CK1, CK13 and CK14 in thirty-three patients with OLP. The biopsied lesions were located in the dorsal surface of the tongue, the palatal keratinized mucosa and the nonkeratinized buccal mucosa. OBJECTIVES: This study aimed to determine the expression of CK1, CK13 and CK14 in oral lichen planus (OLP) and its relations with: clinical patterns, prognosis, drugs and tobacco intake and histopathological features. STUDY DESIGN: Immunohistochemical analysis, retrospective, descriptive, observational and no randomized study. RESULTS: No significant difference was observed in the expression of CK1 in patients with or without drug treatment. No association was found with the amount of drugs intake or smoking nor with the histopathological features examined. Samples immunostained with CK13 were all positive in the suprabasal layers, and 13 of them in the basal layer. In these last ones, statistical analysis showed significance in the grade of vacuolization of the basal layer (p=0.023) and in the degree of exocytosis (p=0.0025), this, making the degree of affection higher for both parameters. Thirty-two tissue sections were immunostained with CK14. CK14 was expressed in the basal layer in 97% of samples and in the suprabasal layer in 94% of samples. CONCLUSIONS: The three CK were altered in OLP. CK1 does not have a direct connection with the presence of orthokeratosis. The finding of the CK13 in the basal layer is related to the agression of the lymphocytic infiltration in the epithelium, due to the basal stratum vacuolization and the increase in lymphocytic exocitosis. The presence of CK14 in the suprabasal stratums is not a parameter to predict malignancy. The CK in OLP do not follow the normal pattern of keratinized or non-keratinized mucosa.

Targeted silencing of DEFB4 in a bioengineered skin-humanized mouse model for psoriasis: development of siRNA SECosome-based novel therapies.

Psoriasis is a complex inflammatory skin disease that presents a wide variety of clinical manifestations. Human ß defensin-2 (hBD-2) is highly up-regulated in psoriatic lesions and has been defined as a biomarker for disease activity. We explored the potential benefits of targeting hBD-2 by topical application of DEFB4-siRNA-containing SECosomes in a bioengineered skin-humanized mouse model for psoriasis. A significant improvement in the psoriatic phenotype was observed by histological examination, with a normalization of the skin architecture and a reduction in the number and size of blood vessels in the dermal compartment. Treatment leads to the recovery of transglutaminase activity, filaggrin expression and stratum corneum appearance to the levels similar to those found in normal regenerated human skin. The availability of a reliable skin-humanized mouse model for psoriasis in conjunction with the use of the SECosome technology may provide a valuable preclinical tool for identifying potential therapeutic targets for this disease.

Factors affecting the formation of membranous substances in the palates of elderly persons requiring nursing care.

OBJECTIVE: To determine the causative factor behind the formation of membranous substances in the mouths of elderly patients requiring nursing care. BACKGROUND: Membranous substances are sometimes observed in the mouths of elderly persons requiring nursing care, and these can lead to bleeding, infection and asphyxiation. MATERIALS AND METHODS: In April 2007, samples were collected from 70 patients at C Hospital, Aichi Prefecture, Japan, who were 65 years or older (median age, 81.1 ± 7.7 years). Sixteen of the subjects were confirmed to have a membranous substance containing a keratin degeneration product that had been derived from stratified squamous epithelium. The samples were examined microscopically, and the presence of epithelial components was confirmed through immunohistochemical staining with anti-cytokeratin-1 antibodies. RESULTS: Decision tree analysis and logistic regression suggest that the leading contributors to the formation of the membranous substances were the method of ingesting nutrients, dryness of the tongue dorsum and open mouth. These three factors are related to elderly persons requiring nursing care with impaired oral cavity function, and it was suggested that dryness of the oral mucosa was the major factor behind the membrane formation.

Biological subtypes of triple-negative breast cancer are associated with distinct morphological changes and clinical behaviour.

Triple negative breast cancer (TNBC) is a heterogeneous group of tumours accounting for approximately 10-20% of all breast carcinomas. To identify biologically distinct subgroups of TNBC and to assess their clinical properties we examined a series of 142 consecutive patients all of which had received adjuvant cytotoxic chemotherapy using a comprehensive panel of immunostains. Hierarchical unsupervised cluster analysis based on the expression of 13 markers permitted separation of four distinct groups (basal A, basal B, basoluminal, luminal) with the main distinguishing features being cytokeratin (Ck5/6, Ck14, Ck19), EGFR, p53, p16, and Ki-67 expression. Clusters differed with respect to patient age, modified Bloom and Richardson grading, the presence of tumour necrosis, growth pattern and survival, both in uni- and multivariate analysis. Basal (A or B) tumours showed a substantially better outcome compared with basoluminal and luminal tumours. Our data underline the heterogeneity of TNBC and characterise potentially relevant biological subtypes.

Identification of endothelial cell surface antigens encoded by genes other than HLA. A combined immunoprecipitation and proteomic approach for the identification of antigens recognized by antibodies against endothelial cells in transplant recipients.

It has been known for some time that transplant recipients may have antibodies to endothelial cells which are not detected on lymphocytes. However, little progress has been made in the analysis of these endothelial antigens. In the present experiments we have attempted to characterize endothelial cell surface antigens to which antibodies were produced during graft rejection. We have used a panel of endothelial cells from umbilical cord veins and found that antibodies with a polymorphic pattern in the panel appeared to correlate with transplant failure of kidney allografts and with the development of transplant-related coronary artery disease (TCAD) in heart transplant recipients. Among 39 patients with kidney allografts, 21 were negative for antibodies to endothelial cells and did well and 18 were positive and had frequent transplant loss (p=0.001). In 18 patients with TCAD and 20 patients of a comparator group without TCAD, association of coronary disease with endothelial cell antibodies was observed (p<0.02). To characterize the endothelial antigens responsible for these serologic reactions we performed immunoprecipitation of reactive antibodies with the corresponding endothelial cell surface antigens, followed by protein identification of the target antigens. Nine proteins were identified in these experiments, 5 were non-polymorphic and appeared to represent autoantigens. Four of the isolated proteins appeared to be polymorphic. They were the Human Major Histocompatibility Complex class I chain-related gene A (MICA), already known to be associated with antibody production and graft failure, human keratin 1, a protein known to be polymorphic and expressed on the surface of endothelial cells, eukaryotic translation initiation factor (EIF) 2A and ErbB3-binding protein 1. The possible role of keratin 1 and the other antigens in allograft rejection requires further investigation.

Quantification of individual proteins in silicone hydrogel contact lens deposits.

PURPOSE: The aim of this study was to quantify specific proteins deposited on daily wear silicone hydrogel lenses used in combination with multipurpose disinfecting solutions (MPDSs) by applying multiple-reaction-monitoring mass spectrometry (MRM-MS). METHODS: Balafilcon A or senofilcon A contact lenses used with different MPDSs on a daily wear schedule were collected. Each worn lens was extracted and then digested with trypsin. MRM-MS was applied to quantify the amounts of lysozyme, lactoferrin, lipocalin-1, proline-rich protein-4, and keratin-1 in the extracts. RESULTS: The amount of protein extracted from the contact lenses was affected by the individual wearers, lens material, and type of care system used. Higher amounts of proteins were extracted from lenses after wear when they were used with an MPDS containing polyhexamethylene biguanide (PHMB) and poloxamer 407 compared with MPDSs containing polyquaternium-1 (PQ-1)/alexidine dihydrochloride with Tetronic 904 or PQ-1/ PHMB with poloxamine and sulfobetaine (p < 0.05). There was a correlation between the amount of lipocalin-1 or keratin-1 extracted from lenses and symptoms of ocular dryness. CONCLUSIONS: The MRM-MS technique is a promising approach that could be used to reveal associations of individual proteins deposited on lenses with performance of contact lenses during wear.

Nonsebaceous lymphadenoma of salivary gland: report of a case with immunohistochemistry and review of the literature.

OBJECTIVE: Nonsebaceous lymphadenomas are rare benign neoplasms. We emphasize the role of immunohistochemistry and attempt to elucidate the pathogenesis by investigating the distribution of 2 transcription factors, MYC and BLIMP1. STUDY DESIGN: A 70-year-old man was evaluated for a 3-cm left parotid mass. Ultrasound-guided fine-needle aspiration biopsy findings were suggestive of a diagnosis of pleomorphic adenoma. A left superficial parotidectomy was performed, and based on histopathology a diagnosis of lymphadenoma, nonsebaceous type, was rendered. RESULTS: The tumor was positive for AE1/3, CKA, BclII, P63, CD79a, CD3, and MYC; focally positive for CK7 and epithelial membrane antigen; and negative for CD10, calponin, CD117, and BLIMP1. CONCLUSIONS: The rarity of nonsebaceous lymphadenoma and its superficial resemblance to commoner salivary gland tumors may present a diagnostic challenge for pathologists. The expression of MYC in the ductal component and the differentiation-related expression of PRDM1 in the superficial keratinizing layers point to a potential role for these 2 transcription factors in the pathogenesis of this neoplasm.

Changes in oral cytokeratin expression in HIV-infected subjects with long-term use of HAART.

OBJECTIVES: The objectives of this study were to determine (i) the expression of oral cytokeratins (CKs) among human immunodeficiency virus (HIV)-infected subjects compared with non-HIV controls, (ii) the oral CK expression in the subjects with highly active antiretroviral therapy (HAART) compared with those without HAART, and (iii) factors associated with the expression of oral CKs. MATERIALS AND METHODS: Oral tissues from buccal mucosa were obtained by punched biopsy in HIV-infected subjects with and without HAART, and non-HIV individuals. The samples were processed for immunohistochemical studies of CK1, CK13, CK14, CK16, and involucrin. The staining intensity was scored and recorded. Logistic regression analysis and multi-way ANOVA test were performed. RESULTS: The expression of CK13, CK14, and CK16 was found to be significantly different between HIV-infected subjects and non-HIV individuals (P < 0.05). The expression of those CKs was also significantly different between those who were and were not on HAART (P < 0.05). No significant difference between the groups was observed regarding CK1 and involucrin. CONCLUSIONS: Oral epithelial cell differentiation as marked by the CK expression is affected by HIV infection and use of HAART. CKs may be the useful biomarkers to identify HIV-infected subjects who are at risk of malignant transformation of the oral mucosa because of HIV infection and HAART.

Tricholemmoma and clear cell squamous cell carcinoma (associated with Bowen's disease): immunohistochemical profile in comparison to normal hair follicles.

There have been only a few reported comparative immunohistochemical studies of normal hair follicles and tricholemmomas. Clear cell squamous cell carcinomas (SCCs), which are derived from Bowen's disease, histopathologically mimic or are difficult to distinguish from tricholemmal carcinoma. The purpose of and methods used in the present study are as follows: (1) evaluation of whether the immunohistochemical profile (cytokeratin (CK)1, CK10, CK17, CD34, and D2-40) in normal hair follicles is retained in tricholemmomas (11 lesions); and (2) a study of the immunohistochemical profile of in situ or superficially invasive clear cell SCCs (associated with Bowen's disease) (10 lesions) to investigate the presence or absence of tricholemmal differentiation markers in these lesions. The present study demonstrated that (1) the immunohistochemical profile of the normal outer root sheath cells was generally retained in tricholemmomas; (2) in contrast to the D2-40 expression in tricholemmomas (only a peripheral pattern, which is similar to that in the normal outer root sheath), the CD34 expression in tricholemmomas represented in a diffuse pattern, a peripheral pattern, and a combined diffuse and peripheral pattern; (3) tricholemmomas are benign neoplasms with outer root sheath (below the isthmus) differentiation, which characteristically show upregulation of CD34 expression with some functionally similar conditions to the terminal hair follicles in the anagen phase; and (4) there is no clear immunohistochemical evidence of tricholemmal differentiation in clear cell SCC (associated with Bowen's disease).

Microchimerism in labial salivary glands of hematopoietic stem cell transplanted patients.

OBJECTIVE: Microchimerism has been extensively investigated in autoimmune diseases, which display similarities with graft-vs-host disease. This study was conducted to investigate the presence of microchimerism in minor salivary glands of hematopoietic stem cell transplanted patients, one of the targets of graft-vs-host disease. METHODS: Labial salivary glands biopsy specimens from 11 stem cell transplanted patients were analysed. The samples were grouped in control (five specimens from a female-to-female transplantation) and study group (five glands from male-to-female transplantation). One male transplanted patient was used as a positive control. Fluorescence in situ hybridization with Y-chromosome probe and immunofluorescence with anticytokeratin AE1/AE3 and CD45 were used to identify Y-chromosome positive glandular epithelial cells from allogeneic hematopoietic stem cell transplanted patients. RESULTS: In the study group, all samples were positive to Y-chromosome and cytokeratin AE1/AE3, in agreement with the pattern exhibited by male labial salivary gland. None of the samples from control group were positive to Y-chromosome despite being positive to cytokeratin AE1/AE3. Positivity to CD45 was not relevant. CONCLUSION: Microchimerism in the labial salivary glands of sex-mismatched stem cell transplanted patients is a real phenomenon. Further studies are necessary to elucidate the impact of this phenomenon on the clinical status of stem cell transplanted patients.

In vivo behavior of complete human oral mucosa equivalents: characterization in athymic mice.

BACKGROUND AND OBJECTIVE: The interest in tissue engineering as a way to achieve repair of damaged body tissues has led to the carrying out of many studies whose results point to the potential effectiveness of these methods. In a previous study, we reported the obtaining of complete autologous oral mucosa equivalents (CAOMEs), characterized by oral immature keratinocytes and stem cells on an autologous plasma and fibroblast scaffold. The purpose of this study is to show their behavior in vivo, by using them as free grafts in experimental animals, and to demonstrate their potential capacity to regenerate oral mucosa. MATERIAL AND METHODS: We engineered CAOMEs, as previously described. All CAOMEs thus obtained were used as free grafts in nu/nu mice. To assess their evolution in vivo, we studied their histological and immunohistochemical features by using AE1/AE3 pancytokeratin, the 5/6 cytokeratin pair, cytokeratin 13, laminin 5, collagen IV, vimentin, p-63 and Ki-67, at 7, 14 and 21 d. RESULTS: The structure became progressively closer to that of oral mucosa samples. Cytokeratin 5/6 staining became increasingly intense in the basal and suprabasal layers, and cytokeratin 13 was exclusively positive in the superficial layers. The basal membrane was completed in 21 d. Vimentin showed a correct formation of the chorion. The increasingly positive staining of p-63 and Ki-67 indicated that the regeneration process was taking place. CONCLUSION: The present study shows the potential regenerative capacity of the CAOMEs by their ability to reach maturity similar to that seen in oral mucosa.

In vitro engineering of complete autologous oral mucosa equivalents: characterization of a novel scaffold.

BACKGROUND AND OBJECTIVE: Restoration of oral mucosa defects by means of in vitro-cultured equivalents has become a valid alternative in the field of oral and periodontics surgery. Although different techniques have been described, none has been able to provide an equivalent with an autologous scaffold for the epithelium. The purpose of this study was to obtain complete autologous oral mucosa equivalents (CAOME) using the patient's own fibroblasts and plasma and to characterize these equivalents both morphologically and immunohistochemically. MATERIAL AND METHODS: We acquired cell types (keratinocytes and fibroblasts) from the same mucosal samples, which were taken from healthy patients who underwent oral surgery. To construct the CAOME, a small sample of blood was obtained from the patient and subsequently processed to obtain a fibrin glue scaffold. All CAOME thus obtained were stained using the standard hematoxylin and eosin method to study their morphological characteristics. To establish the type of cells in the epithelial layer, CAOME were stained with pancytokeratin AE1/AE3, cytokeratins 5/6 and 13, p-63 and Ki-67. Finally, laminin 5 and collagen IV were used to reveal the presence of a basal membrane. RESULTS: The CAOME featured a monolayer of cube-shaped epithelial cells similar to that found on the basal layer of the oral mucosa. Close to the epithelial layer lay the fibrin and fibroblasts-embedded scaffold. The CAOME was positive to pancytokeratin AE1/AE3, cytokeratin 5/6 and p-63. No reaction was found to cytokeratin 13 and Ki-67. There was staining to laminin 5 but not to collagen IV. CONCLUSIONS: It is possible to engineer a CAOME with an epithelium of basal-like and immature keratinocytes, which could potentially reconstruct in vivo loss of tissue.

Adenomatoid odontogenic tumor concomitant with cystic complex odontoma: case report.

This case report describes a 10-year-old female patient with an adenomatoid odontogenic tumor developing together with a cystic complex odontoma. This occurrence is considered very unusual. Immunohistochemical detection of cytokeratins AE1/AE3, CK5, CK8, CK10, CK14, CK19 and Ki-67 was performed.

Identification of promising antigenic components in latent fingermark residues.

An analysis of latent fingermark residues by Sodium-Dodecyl-Sulfate PolyAcrylamide Gel Electrophoresis (SDS-PAGE) followed by silver staining allowed the detection of different proteins, from which two major bands, corresponding to proteins of 56 and 64 kDa molecular weight, could be identified. Two other bands, corresponding to proteins of 52 and 48 kDa were also visualizable along with some other weaker bands of lower molecular weights. In order to identify these proteins, three antibodies directed against human proteins were tested on western blots of fingermarks residues: anti-keratin 1 and 10 (K1/10), anti-cathepsin-D (Cat.D) and anti-dermcidin (Derm.). The corresponding antigens are known to be present in the stratum corneum of desquamating stratified epithelium (K1/10, Cat.D) and/or in eccrine sweat (Cat.D, Derm.). The two major bands were identified as consistent with keratin 1 and 10. The pro-form and the active form of the cathepsin-D have also been identified from two other bands. Dermcidin could not be detected in the western blot. In addition, these antibodies have been tested on latent fingermarks left on polyvinylidene fluoride (PVDF) membrane, as well as on whitened and non-whitened paper. The detection of fingermarks was successful with all three antibodies.

New concepts on the histogenesis of eccrine neoplasia from keratin expression in the normal eccrine gland, syringoma and poroma.

BACKGROUND: Peripheral and luminal layers of eccrine sweat gland ducts are self-renewing structures. Proliferation is restricted to the lowermost luminal layer, but randomly scattered in the peripheral layer. Each layer exhibits differential expression of keratins K5/K14 and K6/K16. Keratin K1 occurs only in peripheral cells and the novel keratin K77 is specific for luminal cells. OBJECTIVES: To investigate the expression of luminal (K77), peripheral (K1) and further discriminatory keratins in two eccrine sweat gland tumours: syringoma, thought to show differentiation towards luminal cells of intraepidermal sweat ducts and eccrine poroma, considered to arise from poroid cells, i.e. peripheral duct cells; and keratinocytes of the lower acrosyringium/sweat duct ridge differentiating towards cells of intradermal/intraepidermal duct segments. METHODS: Paraffin-embedded sections were examined by immunohistochemistry using several keratin, smooth muscle actin and Ki-67 antibodies. RESULTS: We confirmed the ductal nature of syringomas. Despite drastic morphological alterations in both layers, their keratin patterns remained almost undisturbed compared with normal ducts. In eccrine poroma epidermal keratins K5/K14 were ubiquitously expressed in all poroid cells. Cell islands deviating morphologically from poroid cells contained epidermal keratins K1/K10. K77 expression was limited to luminal cells of intact duct structures within the tumours. CONCLUSIONS: Syringomas are benign tumours of luminal cells of the lowermost intraglandular sweat duct. Poroid precursor cells of poromas do not comprise peripheral duct cells nor do poromas differentiate towards peripheral or luminal duct cells. Instead, poroid cells consist only of keratinocytes of the lowermost acrosyringium and the sweat duct ridge and poromas tend to differentiate towards the cells of the upper acrosyringium.