Identification of secretory immunoglobulin A in human sweat and sweat glands

Secretory immunoglobulin A (sIgA) plays an important role in local immune defense mechanisms. Although skin is always exposed to external antigens, the role of local immune defenses involving sIgA in the skin has not been adequately studied. In order to evaluate the presence of sIgA in sweat, we have measured the concentration of sIgA in human sweat by enzyme immunoassay and have localized the components of sIgA in the sweat glands of human axillary skin. The concentration of sIgA in sweat was found to be 10 times higher in men than in women (13.0 +/- 0.9 micrograms/ml versus 1.6 +/- 0.9 micrograms/ml). Secretory component (SC) was localized immunohistochemically in protein synthetic organelles, such as the perinuclear spaces and Golgi complex, in cytoplasmic vesicles, and along the external surface membranes of mucous cells on the terminal segment of eccrine sweat glands. IgA and J chain were present in plasma cells in the protein synthetic organelles. The luminal aspects of eccrine sweat ducts also strongly express SC, as well as IgA and J chain. Neither SC, IgA, or J chain were identified in epithelial cells of apocrine sweat glands. These findings are consistent with the theory that J chain complexed with dimeric IgA is synthesized in plasma cells and is transported by SC-mediated endocytosis transfer across mucous cells of eccrine sweat glands and thus into sweat.     

The demonstration of bacteria on and within the stratum corneum using scanning electron microscopy

Using scanning electron microscopy it has been possible to demonstrate the location of bacteria on and within the stratum corneum of the human foot. Biopsies taken either by sectioning or by removing stratum corneum with cyanoacrylate ester adhesive were examined using a Jeol JSM-T20 scanning electron microscope. Bacteria could be seen easily on specimens from skin which had been occluded to increase the number of bacteria present. On the surface, bacteria were scattered widely in small colonies (usually containing less than ten bacteria). Although bacteria could be seen around the orifice of sweat ducts they did not preferentially favour these sites. Within the stratum corneum, bacteria could be found as relatively large colonies but these were usually associated with sweat ducts or the underside of the furrows in the skin surface. This study suggests that, in normal skin, bacteria are able to colonize both the surface and the depths of the stratum corneum.     

乳房外Paget病中汗腺病理及免疫组化分析

目的：分析乳房外Paget病(EMPD)中汗腺上皮组织CK7和CEA的表达及临床意义。方法：应用免疫组化SP法对15例EMPD皮损和周边正常皮肤CK7和CEA的表达进行检测。结果：15例中有8例在汗腺腺体及导管部见CK7和CEA呈阳性，其中仅5例发现汗腺上皮细胞呈异常改变。结论：免疫组化方法在诊断和鉴别诊断EMPD中汗腺上皮细胞的不典型增生具有一定价值。     

Idiopathic acquired generalized anhidrosis due to occlusion of proximal coiled ducts

Idiopathic acquired generalized anhidrosis is a very rare disease of unknown pathogenesis. We report a 25-year-old man with acquired generalized anhidrosis due to occlusion of the coiled ducts. He did not have sweat secretion over the entire surface of the body, including the palms and soles. Sweat-inducing stimuli provoked tingling pain on the skin. Pilocarpine iontophoresis on the forearm did not induce sweat secretion. Neurological examination did not reveal any abnormality in the central or peripheral nervous system. Skin biopsy showed that the coiled ducts were occluded by an amorphous eosinophilic substance. This amorphous eosinophilic substance was positive with periodic acid-Schiff (PAS) staining and was resistant to digestion by diastase. Electron microscopy demonstrated that the coiled ducts were completely occluded by an amorphous substance. The substance occluding the coiled ducts contained fibrous structures. These findings suggested that the acquired generalized anhidrosis in this patient was caused by occlusion of the coiled ducts by a PAS-positive substance probably derived from dark cell granules.     

Somatostatin receptors are strongly expressed in palmoplantar sweat glands and ducts: studies of normal and palmoplantar pustulosis skin

Background. The acrosyringium is the target for inflammation in the chronic and intensely inflammatory skin disease palmoplantar pustulosis (PPP). The sweat‐gland apparatus seems to be an immunocompetent structure that probably contributes to skin defence. Furthermore, the sweat gland and duct may be a hitherto unrecognized neuroendocrine organ. Aim. To obtain further information about the neuroendocrine properties of the sweat‐gland apparatus by examining expression of the somatostatin receptors (SSTRs) 1–5 in healthy palmar skin and in PPP skin. Methods. Biopsy specimens were taken from 25 patients with PPP and 25 healthy controls. Immunohistochemical analysis was used to investigate expression of SSTRs 1–5. Results. SSTRs 1–5 were expressed in both epidermal and endothelial structures. The staining intensity of the sweat‐gland apparatus was more pronounced than that of the epidermis. Expression differed significantly between lesional PPP and normal plantar skin, with increased expression of SSTRs 3 and 4 in ducts in epidermis, and decreased expression of SSTR 1 in ducts in both papillary and reticular dermis. In specimens with pronounced inflammation, numerous dendritic cells with strong expression of SSTRs 1, 2 and 4 were seen, especially in the papillary dermis. Conclusions. The presence of SSTRs in palmoplantar skin, and specifically at high density in the sweat glands and ducts, might be of particular importance in skin neuroimmunoendocrinology. Although the relevance of the changes in SSTR expression in PPP skin compared with normal skin is unclear, our hypothesis is that these differences might influence the function of both the neuroendocrine and neuroimmunological properties of palmoplantar skin, especially in the sweat‐gland apparatus.     

Proinflammatory cytokines and their corresponding receptor proteins in eccrine sweat glands in normal and cutaneous leishmaniasis human skin

Abstract Paraformaldehyde-fixed biopsy specimens of normal and chronic cutaneous leishmaniasis human skin were investigated for the presence and cellular distribution of interleukin-1α, interleukin-1β, interleukin-6 and tumour necrosis factor-α and the corresponding receptors in eccrine sweat glands, using an indirect immunoperoxidase technique. There was cytoplasmic staining for all 4 cytokines as well as their receptor proteins in the clear cells of the eccrine sweat glands of both normal and inflamed skin specimens. No staining could be seen in the dark cells or the myoepithelial cells, neither in normal nor in inflamed skin. However, a difference between normal and inflamed skin was observed in the ductal syslem. Thus, cell layers of the dermal ducts in leishmaniasis skin were stained for all 4 cytokines, with more intense labelling in the basal cell layer of the coiled ducts, while in the normal skin, an intense staining was more evident in the inner luminal layer, with variable and less intense labelling of the basal layer. The immunolabelling for the cytokine receptors within the dermal ducts exhibited similar staining intensity in both luminal and basal cell layers, except in the case of the IL-6 receptor, which showed a moderate to intense signal in the basal cell layer but a weak staining of the luminal cell layer. Infiltrating inflammatory cells around the sweat gland apparatus in leishmaniasis skin exhibited immunoreactivilies for all cylokines and their corresponding receptors.     

Subclinical dilatation of dermal sweat ducts

1,323 biopsied skin specimens were retrospectively investigated. Dilatation of dermal sweat ducts was observed in 18 specimens (1.36%). They included 7 specimens of malignant and benign neoplasms or nevi, 5 of fibrosis and 6 of various inflammations. The face was the favored site, but it was also seen in other areas. Ten out of 18 specimens were taken in the summer. It was speculated that the massive secretion of sweat and the compression of sweat ducts by several tissue components in the dermis played an important role for the dilatation of the sweat ducts.     

Sweat gland proliferations in scleromyxedema.

Eccrine sweat duct proliferations may be found in various inflammatory and neoplastic skin lesions. We report a patient with scleromyxedema with extensive proliferations of intradermal sweat ducts. Three-dimensional reconstruction demonstrated extensive coiling and branching of the sweat ducts leading into cystic lacunae. In contrast to the basal cell carcinoma that had grown within the scleromyxedematous skin, the ducts close to the lumen stained positive for carcinoembryonic antigen and could therefore be differentiated from basal cell carcinoma. In micrographically controlled surgery of cutaneous epithelial tumors that are located in chronically inflamed skin, such sweat gland proliferations have to be considered as differential diagnosis.     

Apoeccrine sweat duct obstruction as a cause for Fox-Fordyce disease

The pathogenesis of Fox-Fordyce disease has been reported to be hyperkeratosis and obstruction of the upper hair follicle, where the duct of the apocrine sweat gland opens. We report a case of Fox-Fordyce disease with full clinical manifestation. It appeared to be caused by the obstruction of intraepidermal apoeccrine sweat ducts by apoeccrine secretory cells detached and released from the secretory epithelium. A 24-year-old woman visited our clinic with intensely pruritic papules on axillae, mammary areolae, and pubic areas. Histopathologic examination revealed an obstruction of the sweat duct in the epidermis, which opened directly to the skin surface. The closing substance of the duct was an aggregate of epithelial cells, probably derived from the secretory portion. In the dermis, the secretory cells of apocrinelike sweat glands had been detaching from the secretory epithelia. These findings suggest that Fox-Fordyce disease can occur by the mechanism in which apoeccrine secretory cells obstruct sweat ducts.     

Clinical and histopathological studies on spotted grouped pigmented nevi with special reference to eccrine-centered nevus.

Clinical and histopathological studies on 16 cases of spotted grouped pigmented nevus resulted in this disease being classified into at least three types. Characteristic findings of each type are described in this paper, in particular that nevus cell proliferation, a finding common to each type, is closely related pathogenetically to skin appendages, especially with eccrine sweat ducts. The eccrine-centered nevus characterized by Mishima corresponds to the third type, according to the present author's classification. The similar characteristic histopathological finding was also observed in a specimen taken from a black papule in a case of giant pigmented nevus with disseminated pigment cell nevi. We would like to consider that the cells of eccrine-centered nevus are derived from nevoblasts present in the walls of sweat ducts.     

Lectin-binding profiles for normal skin appendages and their tumors

A histochemical investigation of lectin-binding sites was carried out on formalin-fixed paraffin-embedded sections of 60 skin appendage tumors and adjacent normal skin appendages, using four different biotinylated lectins, peanut agglutinin (PNA), Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), and Ulex europaeus agglutinin-1 (UEA-1), and avidin-biotin-horseradish peroxidase labeling. In the secretory segments of eccrine sweat glands, the superficial dark cells showed strong cytoplasmic staining with UEA-1, whereas DBA and SBA strongly stained the plasma membranes of basal clear cells. The acinar cells of apocrine sweat glands revealed sporadic apical membrane staining with all four lectins. In some cases, the luminal membranes of sweat gland ducts showed apical membranous staining with all four lectins. In the hair follicles, the inner root sheath was positive for all four lectins, and the outer root sheath was stained by PNA. The sebaceous ducts, as well as the outer root sheath at the level of sebaceous duct insertion, were also labeled by all four lectins. Sebaceous lobules showed cytoplasmic and membrane staining of mature sebocytes with PNA and SBA. Although sweat gland tumors revealed differences in lectin binding when compared to their corresponding normal tissues, the lectin-binding pattern of pilosebaceous tumors was analogous to the pilosebaceous apparatus.     

Phytohemagglutinin-binding sites in the skin. A useful histochemical marker of acrosyringium and distal portions of intradermal sweat ducts

Phytohemagglutinin (PHA)-binding sites were histochemically investigated in normal adult skin and various skin tumors using peroxidase-labeled lectin. In the normal skin, acrosyringium and distal portion of intradermal duct of eccrine and apocrine sweat glands were intensely stained with PHA. Other elements of the skin were virtually negative. Among various kinds of sweat gland tumors and other skin tumors, syringoma and eccrine porocarcinoma were intensely stained with PHA. Small ductal structures of nodular hidradenoma and mixed tumor of the skin were also stained with PHA. No other skin tumors were positive with PHA staining. The present study clearly showed that PHA is a useful histochemical marker of distal portion of eccrine and apocrine sweat ducts.     

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) in human eccrine sweat glands: demonstration of innervation, specific binding sites and presence in secretions

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) immunoreactivities have been detected in alcohol extracts of human axillary skin using sensitive and specific radioimmunoassays. VIP immunoreactivity (7.63 + 2.33 pmol/g, x + SE, n = 9) was more abundant than PHM immunoreactivity (3.86 + 0.56 pmol/g, x + SE, n = 9). Immunocytochemistry of sections of skin revealed a network of VIP/PHM immunoreactive nerve fibres around the perimeter of eccrine but not apocrine sweat glands. In vitro autoradiography of skin sections using 125I-labelled VIP and PHM, demonstrated binding sites on the membranes of eccrine gland secretory cells. The binding of each radiolabelled ligand was eliminated by the presence of a large molar excess of appropriate cold peptide but was unaffected when incubated with related peptide, indicating the presence of specific binding sites for both VIP and PHM. Radioimmunoassay of Sep-pak concentrated human sweat identified the presence of both VIP immunoreactivity (30.6 pmol/l) and PHM immunoreactivity (43.4 pmol/l). Reverse-phase HPLC analysis of axillary skin extracts and sweat, followed by radioimmunoassay of fractions, identified single resolved peaks of VIP and PHM immunoreactivity with identical retention times to synthetic standards. Eccrine sweat glands in human axillary skin have VIP and PHM peptidergic innervation and possess specific binding sites for each peptide which are both secreted to the surface of the skin.     

P-glycoprotein (ABCB1) expression in human skin is mainly restricted to dermal components

Several transport proteins are constitutively expressed in skin cells, but the putative role of the ABC transporter P-glycoprotein (P-gp) in human skin is yet unknown. Therefore, we analysed mRNA and protein expression and localization of P-gp in human skin. Using qRT-PCR, we demonstrated a strong MDR1 mRNA expression in whole skin specimens and dermis, whereas the expression of MDR1 in epidermis, epidermal keratinocytes or dermal fibroblasts was only weak. Immunohistochemistry confirmed mRNA data and revealed a marked expression of P-gp within sweat ducts, vessels, nerve sheaths and muscles of human skin and a moderate expression in basal epidermis. Our findings closely correlate with previous studies in murine skin supporting the role of P-gp in the uptake of compounds from the epidermal compartment and their secretion into the bloodstream and sweat ducts. It may also prevent the uptake of xenobiotics into the skin by functioning as a barrier located in the dermal vasculature.     

Immunohistochemical demonstration of immunoglobulin A in human sebaceous and sweat glands

Immunoglobulin A (IgA) mediated humoral defense mechanisms have been detected on all mucous membrane surfaces. There are only a few papers about the presence of IgA in human skin. In order to demonstrate the occurrence of IgA in sebaceous and sweat glands, biopsies of normal human skin were investigated and compared to intestinal mucosa. Two different commercially available anti-IgA antibodies were used. For light microscopy peroxidase-anti-peroxidase (PAP) or avidin-biotin complex (ABC) staining was used, and for electron microscopy protein-A-gold (PAG) labeling was performed on tissue sections. Specifically decorated IgA was found in sebaceous glands as well as in various portions of eccrine glands. In sebaceous glands, the maximum of IgA concentration was seen near the mouth of pilosebaceous ducts. Sweat ducts exhibited a continuous coat of IgA, whereas secretory portions contained only singular scattered IgA positive cells. Immunoelectron microscopy suggests endocytotic uptake and processing of IgA in the glandular cells. These results indicate strongly that IgA are secreted by normal human sebaceous and sweat glands. Because it is well known that IgA plays an important role in inactivation of invading viruses, bacteria, and other antigenic structures on mucous membranes, it appears that IgA in sebum and sweat fulfil a similar function on the outer body surface.     

Expression of cadherin cell adhesion molecules during human skin development: morphogenesis of epidermis,hair follicles and eccrine sweat ducts

Summary Expression of E (epithelia) and P (placental) cadherin cell adhesion molecules was examined immunohistochemically using human developing skin. In adult skin, E-cadherin was expressed on cell surfaces of whole epidermal layers including skin appendages, whereas P-cadherin was expressed only on those of basal layers and the outer layers of skin appendages, which was consistent with the compartment of proliferating cells. In fetal skin, while the patterns of E- and P-cadherin expression were generally similar to those in the adult, P-cadherin temporarily showed a unique spatiotemporal expression pattern in developing sweat ducts. During this stage, the expression of P-cadherin accumulated in the epidermal ridges and showed a discrepancy with the compartment of proliferating cells. These results suggest that the expression of P-cadherin is spatiotemporally controlled, and may be closely related to the segregation of basal layers as well as to the arrangement of epidermal cells into eccrine sweat ducts, but is not closely related to cell proliferation.     

Neutrophilic superficial eccrine ductitis: Proposal of a new disease concept

A 3‐year‐old Japanese boy presented with a 3‐month history of itchy erythematous papules on his trunk and forearms, the histologic findings of which were characterized by predominantly neutrophilic inflammation within and around the eccrine sweat ducts and obliteration and disruption of the superficial eccrine sweat ducts. Although the skin disorder had some clinical and histopathologic similarity to miliaria and neutrophilic eccrine hidradenitis, it was ultimately conformed to be neither disorder. Based on this and a case report in the Japanese literature of a 1‐year‐old boy with erythematous eruptions whose clinical and histopathologic findings were similar to those in our case, we propose the skin disorder in our case, referred to as “neutrophilic superficial eccrine ductitis,” as a unique entity.     

Eccrine-centred distribution of human papillomavirus 63 infection in the epidermis of the plantar skin

BACKGROUND: The primary target cell of human papillomaviruses (HPVs) is an unsettled issue. Recent studies have suggested that the hair follicle is an important candidate as the reservoir of certain HPV types. However, little is known about the cells which serve as the target or the reservoir of HPVs in nonhairy palmoplantar skin. OBJECTIVES: To investigate whether the eccrine sweat gland, the only skin appendage in nonhairy palmoplantar skin, also serves as the target or the reservoir of HPVs. METHODS: HPV 63-induced warts were employed in this study, because the virus induces tiny warty lesions of a punctuate appearance in the plantar skin and shows peculiar intracytoplasmic inclusion bodies as a diagnostic histopathological marker of infection: this seemed to provide a useful model for the present study. Serial sections were obtained from the entire body of each biopsy specimen and were investigated histologically, immunohistochemically and using DNA-DNA in situ hybridization (ISH) for the histological localization of HPV 63 infection. RESULTS: On microscopy, HPV 63 histopathological changes were seen closely associated with eccrine ducts. Using ISH, HPV 63 DNA was detected not only in keratinocytes resident around acrosyringia but also in the uppermost portion of the eccrine dermal duct. A few keratinocytes harbouring HPV 63 DNA were also identified in acrosyringeal areas in the normal plantar skin adjacent to the wart lesions. CONCLUSIONS: On the basis of our results, it seems likely that HPV 63 targets keratinocytes resident in or around the eccrine ducts in the plantar skin. The results may also suggest that not only hair follicles but also eccrine ducts serve as reservoirs for certain HPV types, including HPV 63, especially in the nonhairy plantar skin.     

Enzyme immunoassay for secretory immunoglobulin A on skin surface and in sweat

Recently secretory IgA (S-IgA) was found to be secreted from the eccrine gland. By using a sandwich enzyme immunoassay, we measured the concentration of S-IgA 1) in sweat (sweat S-IgA) and 2) in the extract buffer obtained by pipetting++ on the skin (skin surface S-IgA). Skin surface hydration and skin surface lipid were measured at the sites where the samples of skin surface S-IgA were collected. (These measurements were taken immediately after the buffer was pipetted). The quantity of both sweat S-IgA and skin surface S-IgA differed according to the sites where they were collected. Sites in order of decreasing sweat S-IgA level: face, chest, forearm. Sites in order of decreasing skin surface S-IgA level: face, chest, palm, forearm, sole. (Skin surface S-IgA levels on palm and forearm were approximately equal). Although the amount of skin surface S-IgA was not related to the skin surface hydration, there was a significant correlation between skin surface S-IgA and skin surface lipid.     

Normal and PPP-affected palmoplantar sweat gland express neuroendocrine markers chromogranins and synaptophysin differently

Earlier findings indicate the acrosyringium as the target for the inflammation in the chronic and intensely inflammatory skin disease palmoplantar pustulosis (PPP). The sweat gland apparatus seems to be an immune-competent structure that probably contributes to the defence of the skin. Furthermore, the sweat gland and duct may be a hitherto unrecognized neuroendocrine organ because it expresses cholineacetyl-transferase and acetylcholinesterase, nicotinic receptors, beta-adrenergic and angiotensin receptors. The aim of this study was to obtain further information about neuroendocrine properties of the sweat gland apparatus by examining the expression of common neuroendocrine markers synaptophysin and chromogranins A and B in healthy palmar skin and in PPP skin. Synaptophysin and chromogranins were expressed in the sweat glands and ducts with some variation in the pattern and intensity of the expression. In PPP skin the expression differed, being higher and lower, depending on the part of the sweat duct. Chromogranins were further expressed in the epidermis, endothelium and inflammatory cells, but its intensity was weaker in epidermis than in the sweat gland apparatus. In most cases, chromogranins in epidermis in involved PPP were weakly expressed compared to healthy controls. The presence of synaptophysin and chromogranins in palmoplantar skin may have marked neuroendocrine effects, and the palmoplantar skin is likely to have important neuroimmuno-endocrine properties. Moreover, the altered chromogranin expression in PPP skin might influence both the neuroendocrine and neuroimmunologic properties of palmoplantar skin in these patients. These results indicate important neuroendocrine properties of the palmoplantar skin.