T-cell subsets in drug-induced toxic epidermal necrolysis. Possible pathogenic mechanism induced by CD8-positive T cells

A patient with bromisovalum-induced toxic epidermal necrolysis showed pronounced delayed hypersensitivity to bromisovalum by patch testing. Biopsy specimens from the cutaneous lesion and the site of the positive patch test reaction were analyzed and compared immunohistologically. The findings were similar: most of the mononuclear cells disposed along the dermoepidermal junction and migrating into the epidermis were CD8-positive lymphocytes, whereas the dermal inflammatory infiltrates were composed predominantly of CD4-positive lymphocytes. This case showed the potential usefulness of patch testing in evaluating cases of toxic epidermal necrolysis. We believe that delayed hypersensitivity plays a crucial role in the development of drug-induced toxic epidermal necrolysis. Furthermore, potential effector cells with phenotypic characteristics of CD8-positive lymphocytes (suppressor/cytotoxic T cells) seem to represent important mediators of the epidermal damage of the cutaneous lesion in our case.     

Dynamic changes in the epidermal OKT6 positive cells at mild irritant reactions in human skin

In the present study we induced mild irritant contact reactions by using 0.5% sodium lauryl sulphate (SLS) in distilled water or with distilled water in patch tests for 6 or 24 hours. The biopsies were taken at 6, 24, 48 and 96 hours. Light and electron microscopy were used to assess the irritant reactions produced and the monoclonal antibody OKT6 was used for the detection of the LCs. The number of the epidermal OKT6 positive dendritic cells was found to be increased at 48 and 96 hours after the exposure to SLS and at 96 hours in the water patch tests. It is concluded that mild irritant stimuli cause an increase in the LCs (OKT6 positive cells) and thus might influence and modulate the response to subsequent exposures to allergens.     

Cutaneous side-effects of transdermal iontophoresis with and without surfactant pretreatment: a single-blinded, randomized controlled trial

BACKGROUND: Iontophoresis, a method that facilitates drug transport across skin by an external electrical field, offers the possibility for long-term transdermal delivery of compounds in a well-controlled manner. In general, the literature supports the contention that iontophoresis is a safe procedure. However, there are important medical issues concerning the epidermal and dermal effects of iontophoresis that have not been extensively investigated. Specific and strictly controlled studies on the dermal effect of iontophoresis are scarce. OBJECTIVES: The aim of this study was to investigate the cutaneous side-effects of transdermal iontophoresis application in healthy human volunteers. METHODS: This was a single-blinded, randomized and parallel design study. In one group (n=12) subjects were treated nonocclusively with a surfactant formulation followed by iontophoresis (3-h application at a current density of 250 microA cm(-2)). In another group (n=12) iontophoresis alone was performed. No drug was included in these studies. The corresponding passive treatments served as controls. Noninvasive methods including sensation record, transepidermal water loss (TEWL), skin colour and the visual scoring were used to assess cutaneous effects. RESULTS: Tingling and itching were commonly experienced in the first 30 min of the current application. Iontophoresis in combination with the pretreatment induced significant increases in TEWL values and in skin redness, and resulted in slight to mild erythema and oedema compared with the control. Compared with the iontophoresis alone, the presence of surfactant pretreatment caused slightly more skin irritation (erythema and oedema) but did not further disturb the skin barrier function. CONCLUSIONS: The transdermal iontophoresis challenges the skin barrier function and induces transient mild skin irritation, but does not cause any permanent damage to the skin when applied for 3 h at a current density of 0.25 mA cm(-2).     

Peroral nickel provocation in nondyshidrosiform and dyshidrosiform nickel eczema

The flare-up of pompholyx-type nickel eczema induced by oral nickel challenge has been dealt with in several publications. To compare the reactivity of non-pompholyx and pompholyx-type nickel eczema, we challenged three groups of female volunteers (7 with non-pompholyx-type and 12 with pompholyx-type nickel eczema plus 10 control subjects without nickel allergy) with an oral dose of 2.5 mg nickel. By patch testing we additionally determined the degree of cutaneous nickel sensitivity using a series of nickel sulfate dilutions (5.0-0.00001%) and an possible cobalt allergy using 1% cobalt chloride. In 8 of the 19 patients with nickel allergy, the oral nickel challenge was positive (rash, flare-up at sites of healed eczema and former nickel patch tests, and worsening of preexisting eczema; acute pompholyx lesions only in patients with pompholyx-type eczema). The positive results showed the same frequency in non-pompholyx eczema (43%) as in the pompholyx type (42%). Moreover, no substantial difference was found in the degree of cutaneous nickel sensitivity between the two groups of eczema, and there was no correlation between these results and the outcome of the oral nickel challenge. An additional cobalt allergy was recorded significantly more often in pompholyx-type eczema (P = 0.048), yet there was no influence on the oral nickel challenge. The laboratory parameters examined (differential white cell count and total IgE) did not differ in either of the two eczema groups and did not change substantially during nickel challenge reactions.     

Nickel chloride/chlorides of divalent metal interactions in nickel-sensitive subjects

Abstract To verify if the counter-ion Cl^? permits the same interactions between nickel and divalent metals with physicochemical similarities as the counter-ion SO₄^? does, 50 sensitive subjects to nickel sulfate 5% pet. who previously gave positive patch test reactions either to 8 μl of aq. nickel sulfate 0.1 M or to 8 μl of aq. nickel chloride 0.1 M, or to both, were patch retested simultaneously to 8 μl of respectively, aq. nickel sulfate 0.1 M and aq. nickel chloride 0.1 M, and to 8 (il of aq. mixed solutions containing, respectively, nickel chloride 0.1 M +magnesium chloride 0.3 M, nickel chloride 0.1 M+ zinc chloride 0.3 M, nickel chloride 0.1 M+zinc chloride 0.5 M, nickel chloride 0.1 M + manganese chloride 0.3 M, and nickel chloride 0.1 M + manganese chloride O.5 M. Whilst 4 subjects gave a positive patch test response to only nickel sulphate. 8 gave a positive response to nickel chloride alone and the remaining 38 gave a concomitant positive response to both. In all subjects who gave positive responses to nickel chloride, the chlorides of divalent metals were not able to inhibit or reduce the positive reaction. 25 healthy subjects patch tested to both single salts and mixed solutions, and all gave negative responses. 9 of the 50 subjects, 4 who previously gave positive reactions to only nickel chloride 0.1 M, and 5 with concomitant reactions of equal intensity to both nickel chloride and nickel sulfate 0.1 M, were patch retested simultaneously to 8 μ1 of, respectively, aq. nickel sulfate 0.1 M, aq. nickel chloride 0.1 M and aq. mixed solutions containing nickel sulfate (0.1 M) mixed with sulfates (0.3 M) and nickel chloride (0.1 M) mixed with chlorides of Mg, Zn, Mn (0.3 M). Whilst the mixed sulfate solutions were able to reduce nickel sulfale, 0.1 M patch test positive reactions, those containing chlorides, at all concentrations tested, did not inhibit the nickel chloride reactions in any of the subjects. The results of the tests to chlorides, compared to those reached on testing to sulfates of the same metals, lead us to hypothesize that the anion probably affects the uptake and local tissue distribution of the metal, modulating in this way, together with the individual cutaneous ligands, its effects.     

In vitro and in vivo evaluation of the effect of barrier gels in nickel contact allergy

The protective effect of various ethylenediaminetetraacetate (EDTA) barrier gels on nickel skin penetration was investigated in an in vitro model using human skin. Application of the gels seemed to cause an increased release of nickel from nickel alloys. This nickel did not penetrate the skin barrier but was found to be immobilized on the skin surface. This emphasized the importance of washing the skin surface to remove any surplus of barrier formulation after use, since considerable amounts of nickel will be bound in this formulation. It was found that application of the barrier gels beneath the nickel alloy in contact with the skin significantly reduced the amount of nickel found in the epidermal skin layer. In vivo patch testing with a disc of nickel alloy, with and without use of barrier gel, was performed in 21 nickel-sensitive patients. Patch testing with the nickel alloy without use of barrier gel resulted in positive patch test reactions in 11/21 (52.4%) of the patients tested. Application of a Carbopol gel with 10% CaNa₂-EDTA beneath the nickel disc completely abrogated the allergic contact response in all 21/21 (100%) patients. A Carbopol gel without CaNa₂-EDTA was less effective, inhibiting the response in 15/21 (71.4%). A high concordance was found between epidermal nickel levels found in vitro and the in vivo patch test.     

Flare-up reactions after oral challenge with nickel in relation to challenge dose and intensity and time of previous patch test reactions

BACKGROUND: In this study we have taken an interest in systemic exposure to nickel in patients with delayed hypersensitivity to nickel. OBJECTIVE: The aim of the study was to more closely investigate the importance of factors such as ingested nickel dose, time interval between nickel patch testing and oral nickel challenge as well as degree of nickel hypersensitivity in relation to flare-up reactions. METHODS: Thirty nickel-sensitive female subjects were patch tested with a serial dilution of nickel sulfate in water on 4 different test occasions during a period of 7 months. One month after the last patch test the patients were randomly divided into 3 different groups. The patients in the groups were challenged orally with a placebo capsule, 1.0 mg nickel, or 3.0 mg nickel. RESULTS: None of the patients challenged with placebo had flare-up reactions of earlier patch test sites, but 2 of the patients challenged with 1.0 mg nickel and all of the patients challenged with 3.0 mg nickel had flare-up reactions. There were significantly more flare-up reactions of the most recent patch test sites (1 month) compared with the most distant (8 months) test sites. There was also a statistically significant positive correlation between the intensity of previous positive patch tests and the flare-up reactions. CONCLUSION: In the assessment of the possibility of systemic allergic contact dermatitis from nickel, the dose as well as the intensity and time since previous nickel eczema have to be considered.     

Keratinocyte-expression of interleukin-6 but not of tumour necrosis factor-alpha is increased in the allergic and the irritant patch test reaction.

The cytokine expression on epidermal cells in the allergic patch test reaction (APR) and irritant patch test reaction (IPR) was studied using antibodies against rIL-6, rTNF alpha, rIL-1 alpha and rIL-1 beta in a histochemical biotin-avidin technique. Nickel sulphate was used for APR in 5 nickel allergic patients and sodium lauryl sulphate for IPR in 5 healthy individuals. The individuals served as their own control. Enhanced keratinocyte expression of IL-6 was observed in APR and IPR, whereas staining for TNF alpha remained unaltered compared with non-tested and petrolatum-tested skin. Staining for IL-1 alpha and IL-1 beta proved negative in all specimens. Double-staining experiments demonstrated that epidermal and dermal OKT-6 (CD1) positive Langerhans cells (LC) remained negative for all cytokines. These results demonstrate that enhancement of keratinocyte-bound IL-6 does not induce TNF alpha, IL-1 alpha/beta or IL-6 expression by LC during APR or IPR, and that enhanced keratinocyte expression of IL-6 fails to distinguish between these two reactions.     

Iontophoresis for Enhancing Penetration of Dermatologic and Antiviral Drugs

Iontophoresis is the process of introducing ionic drugs into the body for therapeutic purposes. Although iontophoresis has the potential for systemic therapy, it has mainly been used for local therapy at body surfaces. Many ionic drugs are available including lidocaine, epinephrine, methylprednisolone succinate, dexamethasone phosphate, several antivirals, various antibiotics, and other specific drugs. The use of an indicated ionic drug by iontophoresis offers a broad potential for promoting the development of more effective therapies in dermatology. Iontophoresis of ionized drugs provided a 20–60 fold increase in penetration over topical application. Iontophoresis for dermatological use requires that: a) a charged drug be placed at an electrode having a polarity the same charge as the drug, b) the condition or disease under treatment be at or near the body surface, and c) a modern, sophisticated source of direct current, with appropriate accessories, be used. The current source must have features that make it not only effective, but also safe for application to the patient. Modern systems for application of drugs by iontophoresis have features that make the process simple and efficient for use in practice. Iontophoresis has a long history of use, having been suggested for various therapies for many years in medicine, physical therapy and dentistry. Pilocarpine iontophoresis is a preferred method for cystic fibrosis detection. Also, lidocaine iontophoresis has been advocated to anesthetize the tympanic membrane before myringotomy. Anesthesia of the skin to a depth of 1.0 cm or more has been reported in double-blind studies of human volunteers. Local anesthesia by iontophoresis was reported to be effective for: 1) cutaneous cutdowns in patients requiring kidney dialysis, 2) delicate eyelid surgery, as the sole anesthetic, 3) preinjection topical anesthesia, and 4) shave biopsies of skin lesions. The use of iontophoresis for treating difficult cases of hyperhydrosis is quite popular among dermatologists. The present report emphasizes uses of iontophoresis in dermatology and is divided into discussion of studies using iontophoresis for postherpetic neuralgia, local anesthesia, antiviral therapy, and for corticosteroid therapy of nonspecific inflammatory lesions. Over 1250 patients have been treated for postherpetic neuralgia by corticosteroid iontophoresis at 6 medical centers with 60–80% of patients showing a major therapeutic response with return to a tolerable pain level. Double-blind studies of varicella zoster (active and postherpetic) and herpes simplex have proven that iontophoresis is a valuable modality for treating viral diseases of the skin. Many other uses for iontophoresis have been proposed in the literature that involves several hundred research papers, several textbooks and many book chapters. Review of the literature supports the concept that iontophoresis provides an optimal method for drug application in therapy of surface tissues.     

Iontophoresis and sonophoresis stimulate epidermal cytokine expression at energies that do not provoke a barrier abnormality: lamellar body secretion and cytokine expression are linked to altered epidermal calcium levels

We performed this study to identify whether the expression of epidermal cytokines is altered by changes in epidermal calcium content, independent of skin barrier disruption. Iontophoresis and sonophoresis with the energies that do not disrupt the skin barrier, but induce changes in the epidermal calcium gradient, were applied to the skin of hairless mice. Immediately after iontophoresis and sonophoresis, immersion in a solution containing calcium was carried out, and iontophoresis in either high- or low-calcium solutions was performed. The biopsy specimens were taken for real-time quantitative RT-PCR to detect changes in mRNA level of interleukin-1alpha (IL-1alpha), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta in the epidermis and for immunohistochemical stain with primary antibodies to IL-1alpha and TNF-alpha. The expression of each cytokine mRNA increased in the epidermis treated with iontophoresis and sonophoresis compared to a nontreated control as well as in tape-stripped skin used as a positive control and was lower after immersion in a high-calcium solution than in low-calcium solution. IL-1alpha and TNF-alpha immunohistochemical protein staining increased with iontophoresis at low calcium. These studies suggest that changes in epidermal calcium can directly signal expression of epidermal cytokines in vivo, independent of changes in barrier function.     

The crucial role of human dendritic antigen-presenting cell subsets in nickel-specific T-cell proliferation

In the majority of patients, allergic nickel contact dermatitis is associated with a proliferative response of peripheral blood T lymphocytes to nickel sulfate. Optimal proliferation was found in a concentration range of 1-2 X 10(-4) M nickel sulfate. Nickel-specific response of purified peripheral blood T cells requires the presence of antigen-presenting cells (APC). Both peripheral blood monocytes and skin-derived epidermal cells could function as APC, but epidermal cells were shown to be more potent than monocytes. By testing FcR+ monocytes and FcR- circulating dendritic cells for their antigen-presenting capacities, it was found that the critical APC within the fraction of monocytes is the circulating dendritic cell. Testing highly purified T6+ (CD 1) skin-specific dendritic cells (Langerhans cells, LC) and T6- epidermal cells as APC, the critical APC within the fraction of epidermal cells appeared to be the LC. The crucial role of LC was stressed in experiments using T cells from patients exhibiting a positive patch test to nickel but a low or absent proliferative response to nickel by unpurified peripheral blood cells. Whereas addition of peripheral blood APC was ineffective, addition of LC to purified peripheral T cells was shown to overcome this low responsiveness to nickel. These results indicate the crucial role of dendritic APC subsets in nickel-specific T-cell proliferation.     

Long-lasting allergic patch test reactions to nickel sulfate: analysis by nickel quantification and immunocytochemistry

We previously showed the median duration of positive patch test reactions to nickel sulfate(5% pet) was 9 days, and defined as long-lasting (LLAPTR) the 14.3% of reactions that persisted for 17 Days or longer. The pathomechanisms of LLAPTR are unclear, but may involve either localized antigen persistence or abnormal down regulation of the cellular immune response. In this study, we compared (a) the nickel concentration and (b) the immunocytochemical nature of the local immune reaction, between biopsies from LLAPTR ( n = 8) and normally resolving allergic patch lest reactions (NRAPTR) ( n = 8) to nickel sulfate. The concentration of nickel in LLAPTR (median 0.8μg/g, μg/g, range 0.25–3.87 μg/g, mean 0.83μg/g, 95% CI 0 35–1.31) and NRAPTR (median 0.58 μg/g, range 0.2 1.85 μg/g, mean 0.88 μg/g, 95% CI 0.02 1.74) was similar. Activated T lymphocytes, expressing surface IL-2 receptor, HLA DR, DR alpha 1, DP, DQ, and CD2>CD8>CD4 antigens, were seen throughout the dermis and occasionally infiltrating the suprabasal layer of the epidermis in all biopsies. CDI and HLA DR, DR alpha 1, DP, and DQ-expressing Langerhans cells were present throughout the epidermis and occasionally seen in the papillary dermis. HLA DR, DR alpha 1, DP, and DQ antigen expression were also seen on the surface of non-dendritic cells in the epidermis (probably either keratinocytes or T lymphocytes) and vascular endothelial cells in the papillary dermis. There were no significant qualitative or quantitative differences in the immuno-cytochemical nature of the localized immune reaction between LLAPTR and NRAPTR. These findings suggest that the pathomechanism of LLAPTR to nickel sulfate is unlikely to be explained simply on the basis of nickel concentration or the nature of the localized immune reaction at the patch test site.     

Prevalence of delayed hypersensitivity to the European standard series in a self-selected population

There are limited reports of the prevalence of positive reactions in healthy adults to patch tests with standard allergens; there are no recent comprehensive studies from Australia. Healthy adult volunteers (n = 219) from the Western Australian community were patch tested using the European standard series of allergens. Seventy-seven (35%) reacted to at least one allergen, positive patch tests being most prevalent to nickel sulfate (20%), potassium dichromate (9%), cobalt chloride (6%) and fragrance mix (4%). Prevalence of positive patch tests to nickel and chromate was higher than that reported for another healthy population, which may stem from self-selection of volunteers or geographical differences, including extent of exposure to allergens.     

Metal allergy in cashiers. An in vitro and in vivo study for the presence of metal allergy

Thirty healthy cashiers continuously exposed to nickel in coins were tested in vivo and in vitro for the presence of metal contact allergy. A traditional epicutaneous test and lymphocyte transformation test were used. We tested for nickel, cobalt and chromium sensitivity. Seven of the 30 cashiers were patch test positive and 3 were in vitro positive to nickel sulphate. Two were in vivo positive to cobalt and only one in vitro positive. None was chromium allergic. There was no correlation between the exposure time and the lymphocyte response towards nickel. The presence of pierced and non-pierced ear lobes was noted with and without eczema in conjunction with the wearing of ear-rings containing nickel. The lymphocyte reactivity showed no significant difference between these groups. Only 5 out of the 12 with ear lobe dermatitis were patch test positive towards nickel. The data suggest that nickel as test substance or released from nickel-containing jewellery can evoke a cutaneous response which is not always associated with allergy.     

Skin reactions to irritants assessed by non-invasive bioengineering methods

Pathophysiological components of irritant contact dermatitis caused by 3 chemically-different irritants were investigated. 20 healthy volunteers were patch tested with sodium lauryl sulphate, nonanoic acid and hydrochloric acid on the flexor side of the upper arm. The skin response was evaluated after 24, 48 and 96 h by visual scoring and measured by the following bioengineering methods: transepidermal water loss measurement, electrical conductance for measurement of skin hydration, laser Doppler flowmetry for measurement of cutaneous blood flow and 20 MHz ultrasound A-scan for measurement of skin thickness. In spite of homogeneous inflammatory responses, significant differences in the severity of the injury to the skin barrier function caused by the different irritants were found. Also significant differences between irritants were found in the time course of development of maximum irritant reactions. Bioengineering methods indicating inflammatory responses (measurement of blood flow and skin thickness) were helpful in quantifying the irritant response in general, while bioengineering methods indicating epidermal damage (measurement of TEWL and electrical conductance) were helpful in classifying the individual irritants.     

Reactivity to euro coins and sensitization thresholds in nickel-sensitive subjects

BACKGROUND: The 1- and the 2-euro coins consist of nickel alloys, which release nickel. The nickel released by far exceeds the amount allowed by the European Union Nickel Directive referring to products intended to come into direct and prolonged contact with the skin. As there is only temporary contact with the skin, the clinical relevance of nickel-containing coins with regard to nickel dermatitis is a matter of debate, although there is evidence that the nickel released from the coins affects some nickel-sensitive subjects through occupational exposure. OBJECTIVES: Our aim was to study skin reactivity to euro coins, and to correlate the frequency and intensity of coin patch test responses to sensitization thresholds to nickel. PATIENTS AND METHODS: Sixty-four nickel-sensitized and 30 non-nickel-sensitized subjects were patch tested with serial dilutions of nickel sulfate (5, 1, 0.5, 0.1, 0.05, 0.01 and 0.005% in distilled water) and with coins. Italian coins (500, 200, 100 and 50 lira) and euro coins (2 and 1 euros, 20 and 5 euro cents) were used for patch testing and compared. RESULTS: The application of 1- and 2-euro coins to the skin induced eczematous reactions, being more frequent and intense in comparison with those provoked by other coins. A correlation between intensity of responses to coin patch tests and sensitization threshold to nickel was observed. Patients with the strongest reactions to 1- and 2-euro coins showed positive responses to the lowest nickel concentrations. CONCLUSIONS: The nickel content in euro coins represents a possible health hazard, especially for highly nickel-sensitive subjects. We recommend that nickel sulfate patch tests should be performed at different concentrations to determine sensitization thresholds at least in individuals with occupational exposure to coins.     

Elicitation response characteristics to permanent hair dye in paraphenylenediamine-allergic volunteers

BACKGROUND: Elicitation response characteristics to complete permanent hair dye products in paraphenylenediamine (PPD)-allergic volunteers have not previously been explored in detail. OBJECTIVES: To assess the elicitation response characteristics observed in PPD-allergic volunteers upon patch testing with complete hair dyes. METHODS: PPD-allergic volunteers were assigned to 1 of 3 groups depending upon whether they elicited + (group 1), ++ (group 2) or +++ (group 3) reactions following the standard diagnostic procedure. Each group was subsequently patch tested with 2 complete hair dyes (A and B) for 30 min, 1 hr and 24 hr. Patch sites were examined 1 day, 2 days and 3 days after patch removal. RESULTS: Exposure to either hair dye for 30 min or 1 hr was insufficient to yield positive patch test reactions in all of the PPD-allergic patients in groups 1 or 2. Application of either hair dye for 24 hr was sufficient to yield positive reactions in all of the individuals within groups 2 and 3. CONCLUSIONS: The frequency of positive patch test reactions observed following 24-hr exposure to complete permanent hair dyes is comparable to that observed following 48-hr exposure to 1% PPD/petrolatum in those individuals whose degree of sensitization is such that they typically present ++ or +++ reactions diagnostically.     

Fc epsilon R11/CD23 receptor distribution in patch test reactions to aeroallergens in atopic dermatitis.

There is increasing evidence that exposure to organic allergens may induce or exacerbate lesional skin in patients with atopic dermatitis. In this study, patients with atopic dermatitis were patch tested to 11 common organic allergens and to control chambers containing 0.4% phenol and 50% glycerin in 0.9% saline. In biopsies from positive patch test reactions, patch test control skin, lesional eczematous and non-lesional skin from atopic individuals, and normal skin from non-atopic volunteers, the presence and distribution of macrophages (RFD7+), dendritic cells (RFD1+), and Langerhans cells, and the expression of the low-affinity receptor for IgE (CD23) were investigated. In patch test reactions and lesional skin samples, inflammatory infiltrates of diffusely distributed macrophages (RFD7+), dendritic cells (RFD1+), T lymphocytes (RFTmix+), and Langerhans cells (CD1+) were seen, the latter being present in both the epidermis and the dermis. The numbers of Langerhans cells were reduced in the epidermis and increased in the dermis in patch test reactions and lesional skin compared to their controls. Double staining revealed a change in the distribution of CD23 antigen. In patch test control and non-lesional biopsies many macrophages and only a few Langerhans cells within the dermal infiltrates expressed this antigen. In patch test reaction and lesional skin samples, however, the proportion of CD23+ dermal Langerhans cells had increased compared to macrophages. Furthermore, in these latter samples an increased proportion of dermal CD1+ cells expressed the dendritic cell (RFD1+) marker. These results show that following antigen challenge there are marked similarities between the phenotype of the cellular infiltrate in patch test reaction and lesional skin biopsies, and also demonstrate a changing distribution of CD23 on antigen-presenting cells.     

Comparative in situ topoproteome analysis reveals differences in patch test‐induced eczema: cytotoxicity‐dominated nickel versus pleiotrope pollen reaction

Please cite this paper as: Comparative in situ topoproteome analysis reveals differences in patch test‐induced eczema: cytotoxicity‐dominated nickel versus pleiotrope pollen reaction. Experimental Dermatology 2010; 19: 511–517. Abstract: A subgroup of patients with atopic eczema develops acute eczematous reactions to type I allergy‐inducing agents such as pollen that clinically resemble type IV allergies induced by haptens like metal ions. To clarify the underlying immunologic mechanisms, this study was designed to map the inflammatory in situ topoproteome of eczematous responses to grass/birch pollen and nickel by using atopy patch test (APT) and nickel patch test (NPT) as an appropriate clinical model, respectively. Biopsies from NPT (n = 6) and APT (n = 6) with positive reactions at 72 h were analysed by multiple epitope ligand cartography (MELC), which enabled to investigate coexpression of 49 different epitopes immunohistochemically in a single given tissue section. Colocalisation of IgE and FcεRI was investigated by confocal microscopy. Compared with APT responses, NPT reactions were dominated by cytotoxic TIA‐1 + and CD8 + T cells. In contrast, the immune response in APT reactions appeared more pleiotrope – as detected by colocalisation analysis. Multiple combinatorial molecular phenotype (CMP) motifs containing naive, early maturation and memory T cell (CD45RA, CD7, CD44, CD45R0), and general activation markers (CLA, HLA‐DR, CD13, CD29, CD58, CD71, CD138) were significantly higher expressed in APT when compared with NPT reactions. APT response was confirmed to be accompanied by IgE bound to FcεRI. In summary, our results demonstrate that the NPT reaction is clearly dominated by cytotoxic events, while the APT reaction to pollen grains is more heterogeneous and elicits a combined humoral and cellular immune reaction.     

Studies on human epidermal Langerhans cells

Human epidermis from nickel sensitive patients was separated from dermis by means of a suction blister device and dissociated with trypsin. The epidermal cell suspensions obtained contained 3–5% Langerhans cells as judged by immunofluorescence staining of the cells with a rabbit anti-DR anti-serum. The epidermal cells were co-cultured with purified autologous T lymphocytes with or without nickel sulphate. A strong proliferative T lymphocyte response to nickel sulphate was obtained provided epidermal cells were also present. Pretreatment of the epidermal cells with anti-DR antiserum abolished or greatly reduced the response. These data indicate that epidermal cells are able to present nickel sulphate to T lymphocytes in an immunogenic way. Since the responsible cells were DR antigen positive, it is highly probable that the cells responsible for these functions are the Langerhans cells.