Skin Suction Blister Research Articles

Spatial modeling of epidermal nerve fiber patterns.

Peripheral neuropathy is a condition associated with poor nerve functionality. Epidermal nerve fiber (ENF) counts per epidermal surface are dramatically reduced and the two-dimensional (2D) spatial structure of ENFs tends to become more clustered as neuropathy progresses. Therefore, studying the spatial structure of ENFs is essential to fully understand the mechanisms that guide those morphological changes. In this article, we compare ENF patterns of healthy controls and subjects suffering from mild diabetic neuropathy by using suction skin blister specimens obtained from the right foot. Previous analysis of these data has focused on the analysis and modeling of the spatial ENF patterns consisting of the points where the nerves enter the epidermis, base points, and the points where the nerve fibers terminate, end points, projected on a 2D plane, regarding the patterns as realizations of spatial point processes. Here, we include the first branching points, the points where the nerve trees branch for the first time, and model the three-dimensional (3D) patterns consisting of these three types of points. To analyze the patterns, spatial summary statistics are used and a new epidermal active territory that measures the volume in the epidermis that is covered by the individual nerve fibers is constructed. We developed a model for both the 2D and the 3D patterns including the branching points. Also, possible competitive behavior between individual nerves is examined. Our results indicate that changes in the ENFs spatial structure can more easily be detected in the later parts of the ENFs.

Constants of atopic dermatitis recurrence

Skin Inflammation Atopic dermatitis (AD) is an inflammatory disease characterized by itching and widespread eczema. Moderate to severe AD is commonly treated by interleukin (IL)–4Rα blockade with dupilumab yet cessation of this antibody therapy leads to disease recurrence, and the long-term immunologic effects of this treatment remain unclear. Using single-cell RNA sequencing and proteomics of skin suction blisters from patients with AD, Bangert et al. characterized the immunologic milieu in AD skin during this treatment. They showed that dendritic cells and T cells maintained an inflammatory phenotype during long-term IL-4Rα blockade, suggesting that these populations might be central to disease recurrence by maintaining a “disease memory.” These data may contribute to the design of therapies that help to prevent AD recurrence. Sci. Immunol. 6 , eabe2749 (2021).

A Suction Blister Protocol to Study Human T-cell Recall Responses In Vivo.

Cutaneous antigen-recall models allow for studies of human memory responses in vivo. When combined with skin suction blister (SB) induction, this model offers accessibility to rare populations of antigen-specific T-cells representative of the cellular memory response as well as the cytokine microenvironment in situ.This report describes the practical procedure of a cutaneous recall, an SB induction, and a harvest of antigen-specific T-cells. To exemplify the method, the tuberculin skin test is used for antigenic recall in individuals who, prior to this study, underwent a Bacillus Calmette-Guérin vaccination against an infection with Mycobacterium tuberculosis. Finally, examples of multiplex and flow cytometric analyses of SB specimens are provided, illustrating high fractions of antigen-specific polyfunctional CD4+ T-cells available by this sampling method compared with cells isolated from the blood.The method described here is safe and minimally invasive, provides a unique opportunity to study both innate and adaptive immune responses in vivo, and may be beneficial to a broad community of researchers working with cell-mediated immunity and human memory responses, in the context of vaccine development.

A Suction Blister Protocol to Study Human T-cell Recall Responses <em>In Vivo</em>

Cutaneous antigen-recall models allow for studies of human memory responses in vivo. When combined with skin suction blister (SB) induction, this model offers accessibility to rare populations of antigen-specific T-cells representative of the cellular memory response as well as the cytokine microenvironment in situ. This report describes the practical procedure of a cutaneous recall, an SB induction, and a harvest of antigen-specific T-cells. To exemplify the method, the tuberculin skin test is used for antigenic recall in individuals who, prior to this study, underwent a Bacillus Calmette-Guérin vaccination against an infection with Mycobacterium tuberculosis. Finally, examples of multiplex and flow cytometric analyses of SB specimens are provided, illustrating high fractions of antigen-specific polyfunctional CD4+ T-cells available by this sampling method compared with cells isolated from the blood. The method described here is safe and minimally invasive, provides a unique opportunity to study both innate and adaptive immune responses in vivo, and may be beneficial to a broad community of researchers working with cell-mediated immunity and human memory responses, in the context of vaccine development.

Effects of Prednisolone on Serum and Tissue Fluid IGF-I Receptor Activation and Post-Receptor Signaling in Humans.

Short-term glucocorticoid exposure increases serum insulinlike growth factor I (IGF-I) concentrations but antagonizes IGF-I tissue signaling. The underlying mechanisms remain unknown. To identify at which levels glucocorticoid inhibits IGF-I signaling. Nineteen healthy males received prednisolone (37.5 mg/d) and placebo for 5 days in a randomized, double-blinded, placebo-controlled crossover study. Serum was collected on days 1, 3, and 5, and abdominal skin suction blister fluid (SBF; ~interstitial fluid) was taken on day 5 (n = 9) together with muscle biopsy specimens (n = 19). The ability of serum and SBF to activate the IGF-I receptor (IGF-IR) (bioactive IGF) and its downstream signaling proteins was assessed using IGF-IR-transfected cells. Prednisolone increased IGF-I concentrations and bioactive IGF in serum (P ≤ 0.001) but not in SBF, which, compared with serum, contained less bioactive IGF (~28%) after prednisolone (P < 0.05). This observation was unexplained by SBF concentrations of IGFs and IGF-binding proteins (IGFBPs) 1 to 4. However, following prednisolone treatment, SBF contained less IGFBP-4 fragments (P < 0.05) generated by pregnancy-associated plasma protein A (PAPP-A). Concomitantly, prednisolone increased SBF levels of stanniocalcin 2 (STC2) (P = 0.02) compared with serum. STC2 blocks PAPP-A from cleaving IGFBP-4. Finally, prednisolone suppressed post-IGF-IR signaling pathways at the level of insulin receptor substrate 1 (P < 0.05) but did not change skeletal muscle IGF-IR, IGF-I, or STC2 messenger RNA. Prednisolone increased IGF-I concentrations and IGF bioactivity in serum but not in tissue fluid. The latter may relate to a STC2-mediated inhibition of PAPP-A in tissue fluids. Furthermore, prednisolone induced post-IGF-IR resistance. Thus, glucocorticoid may exert distinct, compartment-specific effects on IGF action.

CCL20 neutralization by a monoclonal antibody in healthy subjects selectively inhibits recruitment of CCR6+ cells in an experimental suction blister.

GSK3050002, a humanized IgG1κ antibody with high binding affinity to human CCL20, was administered in a first-in-human study to evaluate safety, pharmacokinetics (PK) and pharmacodynamics (PD). An experimental skin suction blister model was employed to assess target engagement and the ability of the compound to inhibit recruitment of inflammatory CCR6 expressing cells. This study was a randomized, double-blind (sponsor open), placebo-controlled, single-centre, single ascending intravenous dose escalation trial in 48 healthy male volunteers. GSK3050002 (0.1-20mgkg-1 ) was well tolerated and no safety concerns were identified. The PK was linear over the dose range, with a half-life of approximately 2 weeks. Complex of GSK3050002/CCL20 increased in serum and blister fluid with increasing doses of GSK3050002. There were dose-dependent decreases in CCR6+ cell recruitment to skin blisters with maximal effects at doses of 5mgkg-1 and higher, doses at which GSK3050002/CCL20 complex in serum and blister fluid also appeared to reach maximum levels. These results indicate a relationship between PK, target engagement and PD, suggesting a selective inhibition of recruitment of CCR6+ cells by GSK3050002 and support further development of GSK3050002 in autoimmune and inflammatory diseases.

Discovering early diabetic neuropathy from epidermal nerve fiber patterns.

Epidermal nerve fibre (ENF) density and morphology are used to study small fibre involvement in diabetic, HIV, chemotherapy induced and other neuropathies. ENF density and summed length of ENFs per epidermal surface area are reduced, and ENFs may appear more clustered within the epidermis in subjects with small fibre neuropathy than in healthy subjects. Therefore, it is important to understand the spatial structure of ENFs. In this paper, we compare the ENF patterns between healthy subjects and subjects suffering from mild diabetic neuropathy. The study is based on suction skin blister specimens from the right foot of 32 healthy subjects and eight subjects with mild diabetic neuropathy. We regard the ENF entry point (location where the trunks of a nerve enters the epidermis) and ENF end point (termination of the nerve fibres) patterns as realizations of spatial point processes, and develop tools that can be used in the analysis and modelling of ENF patterns. We use spatial summary statistics and shift plots and define a new tool, reactive territory, to study the spatial patterns and to compare the patterns of the two groups. We will also introduce a simple model for these data in order to understand the growth process of the nerve fibres. Copyright © 2016 John Wiley & Sons, Ltd.

A suction blister model reliably assesses skin barrier restoration and immune response

Skin wound healing models can be used to detect changes in immune function in response to interventions. This study used a test–retest format to assess the reliability of a skin suction blister procedure for quantitatively evaluating human immune function in repeated measures type studies. Up to eight suction blisters (~30mm2) were induced via suction on each participant's left and right forearm (randomized order; blister session 1 and 2), separated by approximately one week. Fluid was sampled from each blister, and the top layer of each blister was removed to reveal up to eight skin wounds. Fluid from each wound was collected 4, 7 and 24h after blisters were induced, and proinflammatory cytokines were measured. Transepidermal water loss (TEWL), to assess skin barrier recovery, was measured daily at each wound site until values were within 90% of baseline values (i.e., unbroken skin). Sleep, stress and inflammation (i.e., factors that affect wound healing and immune function), preceding the blister induction, were assessed via activity monitors (Actical, Philips Respironics, Murrysville, Pennsylvania), the Perceived Stress Scale (PSS) and C-reactive protein (CRP), respectively. Area-under-the-curve and TEWL, between blister session 1 and 2, were compared using Pearson correlations and partial correlations (controlling for average nightly sleep, PSS scores and CRP). The suction blister method was considered reliable for assessing immune response and skin barrier recovery if correlation coefficients reached 0.7. Volunteers (n=16; 12M; 4F) were 23±5years [mean±SD]. Time to skin barrier restoration was 4.9±0.8 and 4.8±0.9days for sessions 1 and 2, respectively. Correlation coefficients for skin barrier restoration, IL-6, IL-8 and MIP-1α were 0.9 (P<0.0001), 0.7 (P=0.008) and 0.9 (P<0.0001), respectively. When average nightly sleep, PSS scores and CRP (i.e., percent difference between sessions 1 and 2) were taken into consideration, correlations in immune response between sessions 1 and 2 were improved for IL-8 (0.8, P=0.002) and TNF-α (0.7, P=0.02). The skin suction blister method is sufficiently reliable for assessing skin barrier restoration and immune responsiveness. This data can be used to determine sample sizes for cross-sectional or repeated-measures types of studies testing the impact of various stressors on immune response, and/or the efficacy of interventions to mitigate decrements in immune response to stress.

A suction blister model reliably assesses skin barrier restoration and immune response (734.1)

This study assessed test‐retest reliability of a skin suction blister method for evaluating immune function. Up to 8 blisters (~30 mm2) were induced via suction on participant’s left and right forearm, separated by ~1 week. Fluid was sampled from blisters and the top layer was removed to reveal up to 8 wounds. Fluid was collected from wounds 4, 7 and 24 h post‐blistering, and pro‐inflammatory cytokines were measured. Transepidermal water loss, to assess skin barrier recovery, was measured daily until values were within 90% of unbroken skin. Sleep and stress (i.e., factors affecting wound healing), in the days before blistering, were assessed via activity monitors and the Perceived Stress Scale. This method was deemed reliable if correlations between the left and right arm reached 0.8. Skin barrier restoration for participants (n=16; 12M/4F; 23±5 years [mean±SD]) was 4.96±0.70 and 4.83±0.96 days for sessions 1 and 2, respectively. Correlations for skin barrier restoration, [area‐under‐the‐curve] IL‐6, IL‐8 and TNF‐α were 0.8, 0.9, 0.7, and 0.5, respectively (P&lt;0.001‐P&lt;0.05). When sleep and stress were considered, correlations improved for IL8 (0.8, P=0.002) and TNF‐α (0.7, P=0.01). This suction blister method is reliable for assessing skin barrier restoration and immune response, and can be used to study the functional impact of various stressors on immune function and wound healing.Grant Funding Source: Supported by the U.S. Army Medical Research &amp; Materiel Command

Analysis of spatial structure of epidermal nerve entry point patterns based on replicated data

Epidermal nerve fiber (ENF) density and morphology are used to diagnose small fiber involvement in diabetic, HIV, chemotherapy induced, and other neuropathies. ENF density and summed length of ENFs per epidermal surface area are reduced, and ENFs may appear clustered within the epidermis in subjects with small fiber neuropathy compared to healthy subjects. Therefore, it is important to understand the spatial behaviour of ENFs in healthy and diseased subjects. This work investigates the spatial structure of ENF entry points, which are locations where the nerves enter the epidermis (the outmost living layer of the skin). The study is based on suction skin blister specimens from two body locations of 25 healthy subjects. The ENF entry points are regarded as a realization of a spatial point process and a second-order characteristic, namely Ripley's K function, is used to investigate the effect of covariates (e.g. gender) on the degree of clustering of ENF entry points. First, the effects of covariates are evaluated by means of pooled K functions for groups and, secondly, the statistical significance of the effects and individual variation are characterized by a mixed model approach. Based on our results the spatial pattern of ENFs in samples taken from calf is affected by the covariates but not in samples taken from foot.

A Comparative Proteomic Study of Human Skin Suction Blister Fluid from Healthy Individuals Using Immunodepletion and iTRAQ Labeling

Aberrations in skin morphology and functionality can cause acute and chronic skin-related diseases that are the focus of dermatological research. Mechanically induced skin suction blister fluid may serve as a potential, alternative human body fluid for quantitative mass spectrometry (MS)-based proteomics in order to assist in the understanding of the mechanisms and causes underlying skin-related diseases. The combination of abundant-protein removal with iTRAQ technology and multidimensional fractionation techniques improved the number of identified protein groups. A relative comparison of a cohort of 8 healthy volunteers was thus recruited in order to assess the net variability encountered in a healthy scenario. The technology enabled the identification, to date, of the highest number of reported protein groups (739) with concomitant relative quantitative data for over 90% of all proteins with high reproducibility and accuracy. The use of iTRAQ 8-plex resulted in a 66% decrease in protein identifications but, despite this, provided valuable insight into interindividual differences of the healthy control samples. The geometric mean ratio was close to 1 with 95% of all ratios ranging between 0.45 and 2.05 and a calculated mean coefficient of variation of 15.8%, indicating a lower biological variance than that reported for plasma or urine. By applying a multistep sample processing, the obtained sensitivity and accuracy of quantitative MS analysis demonstrates the prospective value of the approach in future research into skin diseases.

Mast Cells

Mast Cells

Matrix-metalloproteinase-2, -8 and -9 in serum and skin blister fluid in patients with severe sepsis

IntroductionMatrix metalloproteinases (MMPs) have various roles in inflammatory states. They seem to be able to modulate endothelial barriers and regulate the activity of chemokines and cytokines. The timely development of the levels during severe sepsis and thereafter have not been investigated. In addition it was of interest to study alterations of MMP-levels in intact skin, as the skin is the largest barrier against external pathogens and MMPs have not been studied at organ level in human sepsis. The aim of this study was to investigate the timely development of serum and skin MMP-2, -8 and -9 levels in human severe sepsis and their association with disease severity and mortality.MethodsForty-four patients with severe sepsis and fifteen healthy controls were included in this prospective longitudinal study. The amounts of MMP-2, -8 and -9 were analyzed from serum at days 1, 4, 6, 8, and 10, and from skin suction blister fluid at days 1 and 5 from the beginning of severe sepsis. Additionally, samples from the survivors were obtained after three and six months.ResultsThe levels of MMP-2 and -8 were up-regulated in severe sepsis in comparison to healthy controls in skin blister fluid and serum. Compared to the controls MMP-9 levels were lower in sepsis from the fourth day on in serum and both the first and fifth day in skin blister fluid. Active forms of MMP-2 and -9 were present only in severe sepsis. The non-survivors had higher pro- and active MMP-2 levels than the survivors in skin blister fluid samples. Furthermore, MMP-2 levels were more pronounced in blister fluid and serum samples in patients with more severe organ failures. In the survivors at 3 and 6 month follow-up the MMP levels had returned to normal.ConclusionsMMP-2 and -8 are elevated in serum and blister fluid in severe sepsis, implying that they may play a significant role in the pathogenesis of severe sepsis and organ dysfunctions. Active forms of MMP-2 and 9 were only present in patients with severe sepsis, and higher MMP-2 levels in skin blister and serum were associated with more severe organ dysfunctions.

Analysis of Epidermal Nerve Fibers: Comparison of Two Techniques

Histopathologic evaluation of epidermal nerve fibers (ENFs) is a very useful technique for diagnosing small-fiber neuropathies. Clinicians currently use skin-punch biopsy to obtain the tissue sample. To evaluate a less-invasive technique, researchers compared skin-punch biopsy with the investigational suction skin-blister method in 25 healthy volunteers. Tissue samples were obtained from the foot and calf, frozen, and immunostained using antibodies against protein gene product 9.5, an axonal marker, …

Skin blister and skin biopsy to quantify epidermal nerves

Skin biopsy is an important procedure for the diagnosis of peripheral neuropathy. The main indicators of unmyelinated nerve involvement are decreased density and abnormal morphology of epidermal nerve fibers (ENFs). The suction skin blister is an alternative, less invasive method to visualize and quantify ENFs. The blister roof provides an integrated bird's eye view of all ENFs within one tissue specimen. We compared the suction skin blister method to the punch skin biopsy for evaluation of ENFs. Twenty-five volunteers, 35 to 62 years old, without symptoms or history of peripheral neuropathy, and normal by neurologic examination and nerve conduction tests, were studied. One 3 mm punch biopsy and two 3 mm suction blister specimens were collected from the right foot and calf. Comparison between blister and biopsy ENF density was assessed by repeated measures analysis of covariance, accounting for age, gender, and specimen's location. The epidermal roof of the suction skin blister permitted detailed analyses of ENF density, morphology, and distribution across the epidermis and observation of ENF branching pattern. No systematic differences of ENF density were found between skin blisters and biopsies (p = 0.29) or between pairs of blisters from the same location (p = 0.15). ENF density was lower for older subjects (p < 0.01). The suction skin blister method has potential as a diagnostic tool to investigate small fiber neuropathies. It is a minimally invasive and reliable technique, comparable to skin biopsy for determining epidermal nerve fiber density.

Potential of Fibroblast Cell Therapy for Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe inherited skin-blistering disorder caused by mutations in the COL7A1 gene that lead to reduced type-VII collagen and defective anchoring fibrils at the dermal-epidermal junction (DEJ). Presently there are no effective treatments for this disorder. Recent mouse studies have shown that intradermal injections of normal human fibroblasts can generate new human type-VII collagen and anchoring fibrils at the DEJ. To assess potential clinical benefits in humans, we gave single intradermal injections of allogeneic fibroblasts to five subjects with RDEB. We noted increased type-VII collagen at the DEJ at 2 weeks and at 3 months following injection and increased anchoring fibrils, although none of these had normal morphology. No adverse effects, clinical or immunopathologic, were noted. We believe the major effect of allogeneic fibroblasts is to increase the recipients' own COL7A1 mRNA levels with greater deposition of mutant type-VII collagen at the DEJ and formation of additional rudimentary anchoring fibrils. Nevertheless, this mutant protein may be partially functional and capable of increasing adhesion at the DEJ. This is the first study demonstrating that intradermal injections of allogeneic fibroblasts have therapeutic potential in human subjects with RDEB.

An action spectrum (290–320 nm) for TNFα protein in human skinin vivosuggests that basal-layer epidermal DNA is the chromophore

Terrestrial solar UVB radiation ( approximately 295-320 nm) readily induces cyclobutane pyrimidine dimers (CPDs) in human skin DNA that result in characteristic mutations associated with nonmelanoma skin cancer. The proinflammatory cytokine TNFalpha is important in mouse skin chemical carcinogenesis and is thought to also play a role in UVR-induced skin cancer by its immunomodulatory properties. There is some in vitro evidence that CPDs initiate the production of TNFalpha, and we tested this hypothesis by comparing the wavelength dependence (action spectrum) for TNFalpha protein induction in human skin in vivo with our earlier in vivo action spectra for CPD induction in four different epidermal layers of human skin. Normal volunteers (n = 35) were irradiated with physiologically relevant doses of monochromatic UVB (290-320 nm), and TNFalpha concentration was assessed, by high-sensitivity ELISA, in exudates from skin suction blisters raised 8 h after irradiation. An action spectrum, constructed from the slopes of the dose-response curves at the different wavelengths, showed maximal efficacy at 300 nm. An excellent match was observed for TNFalpha and the CPD action spectrum for cells in the lower basal epidermis. These data strongly suggest that UVB-induced photodamage to DNA in the epidermal basal layer is a major trigger for TNFalpha production. The TNFalpha may originate directly from the keratinocytes in this layer or inflammatory cells that are rapidly recruited into the upper dermis (e.g., neutrophils) as a consequence of DNA photodamage to basal-layer keratinocytes.

Radiation-induced changes in skin type I and III collagen synthesis during and after conventionally fractionated radiotherapy

Background and purpose To measure local changes of collagen metabolism in irradiated breast skin and systemic changes in serum during and after radiotherapy and correlate these changes with skin thickness, erythema and palpable subcutaneous induration. Patients and methods Aminoterminal propeptides of type I and type III procollagens (PINP and PIIINP, respectively) were measured from skin suction blister fluid (SBF) in 21 breast cancer patients with breast conserving surgery and conventionally fractionated radiotherapy (RT) to a total dose of 50 Gy. Suction blisters were induced in the operated and contralateral breast skin before RT, at 2.5 weeks, at the end of RT, and at 1, 4, 7, 12 and 24 months post-treatment. Blood samples for serum were taken simultaneously with SBF induction. Skin thickness of the suction blister sites was measured with a high-frequency ultrasound device. The investigated sites were scored for erythema at the end of RT and palpable subcutaneous induration at 1 and 2 years post-treatment. Results In SBF the mean levels of PINP and PIIINP of the operated breast before RT were about 3–4 times higher than those in the contralateral breast due to the operation-related wound healing. The synthesis of PINP in irradiated breast after RT increased 7.7-fold ( P<0.001) 4 months post-irradiation. The PIIINP synthesis was at maximum at 1 month post-irradiation ( P<0.001). Both synthesis stayed elevated until 2 years. The level of PINP correlated significantly with the palpable skin induration at 1 and 2 years ( P=0.038 and P=0.003, respectively). The skin thickness of the irradiated breast was highest at 4 months post-treatment and significantly elevated until 1 year. The skin thickness correlated with the PINP level until 7 months and with PIIINP between 4 and 18 months. The PINP/PIIINP ratio reached the maximum at 4 months and stayed elevated until 2 years. No change in mean serum level of PINP was found during or after RT. Conclusions We demonstrated a maximum and elevated levels for PINP and PIIINP skin collagen metabolism determined from SBF during the 2 years' follow-up. Elevated levels of PINP and PIIINP correlated with the thickening of the skin and subcutaneous induration but not with erythema.

Surface expression of FcϵRI on Langerhans' cells of clinically uninvolved skin is associated with disease activity in atopic dermatitis, allergic asthma, and rhinitis

Background: FcϵRI expressed on the surface of human epidermal Langerhans' cells facilitates uptake of IgE-associated allergens and plays a pivotal role in the pathogenesis of atopic dermatitis. Seminal results from studies investigating Langerhans' cell FcϵRI in skin biopsy sections or epidermal cell suspensions demonstrate the highest receptor expression in lesional skin of patients with active atopic dermatitis. Objective: We sought to investigate and localize FcϵRI expression on Langerhans' cells within a minimally disturbed tissue environment in clinically uninvolved skin and to compare receptor expression between healthy donors and patients with atopic dermatitis or other allergic diseases. Methods: Intact epidermal sheets from skin suction blisters, immunofluorescently stained with Langerhans' cell markers and anti-FcϵRIα (mAbs 15E5 and 22E7) or anti-IgE, were examined by means of confocal microscopy. Samples incubated with anti-FcϵRIα before or after cell fixation-permeabilization were compared to discriminate between cytoplasmic and membrane localization. Results: Cytoplasmic FcϵRI α chain was found in Langerhans' cells from all donors, irrespective of atopic status. Surface FcϵRI-bound IgE was detected in the skin of individuals with active atopic dermatitis and in the skin of those with active asthma or rhinitis. No surface FcϵRI was expressed in the skin of patients with a clinical history of atopic dermatitis, asthma, or rhinitis whose disease was in remission or in the skin of nonatopic individuals. Conclusion: In clinically uninvolved skin, Langerhans' cell-surface FcϵRI expression is not only linked to atopic dermatitis but is also generally associated with allergic disease. This supports the concept of a systemic regulatory mechanism associated with active allergic disease, which is further aggravated by local inflammation in atopic skin lesions. (J Allergy Clin Immunol 2003;112:411-9.)

Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 4

A severe sensory neuropathy, mostly involving large myelinated sensory fibers, characterizes Friedreich ataxia since the early onset. Recently, an involvement of unmyelinated nerve fibers has been observed studying cutaneous innervation by means of immunohistochemical techniques and confocal microscopy. Quantification of epidermal nerve fibers (ENFs) by skin biopsy has been extensively used in the last decade to evaluate small‐fiber neuropathies. This minimally invasive procedure, repeatable over time, allows to monitor a neuropathic process. An even less invasive technique is the biopsy of the only epidermis, obtained removing the roof of suction skin blister, sparing basal membrane and vessels. Skin blister, beside a diagnostic tool in sensory neuropathies, is a wound model to study nerve regeneration in human epidermis. The aim of our research was to define the regenerative capability of cutaneous nerve fibers in patients affected by Friedreich's ataxia evaluating time‐course and patterns of nerve fibers regeneration. Six patients (4F, 2M, age 19–34) affected by genetically determined Friedreich ataxia were included in our study. In each subject we induced 5 couples of 2 mm blisters on the forearm. At different time points (1–2–3–4 weeks after blister induction) one blister was removed by 3 mm punch skin biopsy and one was reblistered (3‐mm blister) and the roof removed. The larger size of these biopsies and blisters allowed at including normal skin immediately adjacent to the blister wound. Epidermal nerve fibers were visualised using antibodies to the pan‐neuronal marker protein gene product 9.5 (PGP 9.5) on frozen sections from skin biopsies and on the whole blister roofs. Quantification of ENFs was performed on skin sections using digitised images acquired by confocal microscopy (CARV) and Neurolucida software. Blister allowed to have a panoramic and global view of the regenerative process especially of the collateral extension of axons from adjacent normal epidermis, while biopsy allowed to observe the sprouting from the subepidermal neural plexus. Both these phenomena resulted markedly evident in all FA subjects indicating a normal capability of nerve fibers to regenerate. Blister wound probably induces the release of nerve growth factors stimulating nerve regeneration as in normal subjects. At least for the short period of observation (four weeks) nerve fibers maintained this capability challenging the noxa patogena that leads to their loss.