Effect of skin barrier competence on SLS and water-induced IL-1alpha expression

For screening of a potential irritant it is essential that an early marker for irritation should be chosen which could be detected before the physiological signs of irritation occur. Interleukin 1 alpha (IL-1alpha) is widely accepted as such a marker in both in vivo and in vitro test systems. In this study, we have determined the mRNA levels of IL-1alpha in the epidermis after topical application of sodium dodecyl sulphate (SLS) in both a commercially available epidermal kit (EpiDerm) and in excised skin. Furthermore, we have determined the effect of water, the vehicle for SLS, on IL-1alpha mRNA levels. Topical application of water to excised skin increases IL-1alpha mRNA levels sixfold in the epidermis whereas topical application of water to EpiDerm cultures did not alter IL-1alpha mRNA levels. This is explained by the finding that EpiDerm cultures have a sub-optimal barrier function when compared with excised skin - topical application of SLS was clearly toxic at much lower concentrations in EpiDerm cultures (0.2% SLS) than in excised skin (5% SLS). Also caffeine penetration was 10-fold higher through EpiDerm cultures than through the excised skin. Therefore, incubation of control EpiDerm cultures at 100% humidity effectively mimics topical exposure to water. An additional increase in IL-1alpha mRNA levels observed between topical application of water and SLS is similar (about threefold) in both experimental systems. In conclusion, in vitro reconstructed epidermis models, such as EpiDerm, can be used as a predictive model for irritancy screening. However, great care should be taken when interpreting the results due to the fact that EpiDerm cultures do not have a competent barrier function and therefore lower irritant concentrations are required than in in vivo or ex vivo studies in order to induce cytotoxic effects. Furthermore, the irritant effects of the vehicle should not be neglected. Our results show clearly that the topical application of water to excised skin results in increased levels of IL-1alpha mRNA in the epidermis. This is a cytokine that is widely used as an early marker for skin irritation.     

A stronger patch test elicitation reaction to the allergen hydroxycitronellal plus the irritant sodium lauryl sulfate

Household and cleaning products often contain both allergens and irritants. The aim of this double-blinded, randomized, paired study was to determine whether patch testing with an allergen (hydroxycitronellal) combined with an irritant [sodium lauryl sulfate (SLS)] cause a stronger patch test elicitation reaction than patch testing with the allergen (hydroxycitronellal) alone, in patients previously patch tested positive to hydroxycitronellal. A stronger patch test elicitation reaction was defined as at least 1 day of patch test reading showing more positive patch tests (+, ++ or +++) on the forearm patch tested with 6 concentrations of SLS plus hydroxycitronellal than on the forearm tested with 6 concentrations of hydroxycitronellal alone and no day of patch test readings showing more positive tests on the hydroxycitronellal forearm. 15/20 (75%) had at least 1 day of patch test reading with more positive patch tests on the forearm patch tested with SLS plus hydroxycitronellal and no day of patch test readings with more positive patch tests on the forearm tested with hydroxycitronellal (P = 0.0253). Estimation of the blood flow with laser Doppler supported these findings.     

ETAF/Interleukin-1 and epidermal lymphocyte chemotactic factor in epidermis overlying an irritant patch test

We have previously demonstrated that the epidermal content of the lymphocyte activating peptide ETAF/IL-1 and lymphocyte chemotactic factor (ELCF) increases during the development of a cell-mediated immune reaction, represented either by the tuberculin skin reaction or by a positive patch test in patients with contact allergy. The present study describes the epidermal content of these mediators during an irritant patch test reaction. The results show that ELCF, but not ETAF/IL-1, is significantly increased in the epidermis of an irritant patch test with 3% SLS or 5% croton oil, irrespective of the intensity of the clinical patch test reaction. We observed that simple occlusion of epidermis did not induce ELCF activity in healthy persons, whereas patients with previous or current eczema had a significant release of ELCF following such occlusion. These results seem to indicate that there exist important functional differences between allergic and irritant patch test reactions with respect to the presence of lymphocyte activating signals in epidermis.     

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.     

健康成人皮肤对十二烷基硫酸钠刺激反应的反射式共聚焦显微镜特征分析

目的 观察十二烷基硫酸钠（SLS）刺激后18 ~ 60岁健康人皮肤反射式共聚焦扫描显微镜（RCM）特征的差异,分析年龄和性别对皮肤反应的影响,同时初步探讨RCM在客观评价皮肤反应中的价值。方法 采用封闭式斑贴试验,分别将0.1%和0.5% SLS贴敷于120例健康受试者背部48 h,并于去除后不同时间点进行临床评估和RCM检测。结果 0.1%和0.5% SLS组皮肤刺激反应的RCM特征主要有角化不全、角质层结构不清、棘层海绵水肿、表皮炎症细胞浸润和真皮乳突毛细血管扩张等。去除0.1%和0.5%SLS 刺激后24 h,RCM特征发生率达到高峰,其中真皮毛细血管扩张的发生率分别高达66.7%和95.0%。0.5% SLS去除后24 h,男性海绵水肿的发生率为68.9%（42/61）,显著低于女性［84.7%（50/59）,χ2 = 4.24,P < 0.05］; 0.1%SLS去除后24 h,18 ~ 40岁年龄组人群棘层海绵水肿的发生率为53.3%（32/60）,显著高于41 ~ 60岁［35.0%（21/60）,χ2 = 4.09,P < 0.05］;其余RCM参数,在0.1%和0.5% SLS刺激去除后,不同性别或不同年龄组之间差异均无统计学意义（P > 0.05）。临床评估显示去除0.1%和0.5% SLS后24 h,男女皮肤刺激反应发生率差异均无统计学意义（均P > 0.05）,18 ~ 40岁和41 ~ 60岁两个年龄组之间差异也无统计学意义（均P > 0.05）。Spearman相关性分析显示,临床评估结果与RCM特征之间具有良好的相关性,其中,去除0.1% SLS后24 h,海绵水肿和真皮毛细血管扩张与临床评估结果的相关系数均高达0.77（P < 0.001）。但去除SLS 0.5 h后,0.1%和0.5% SLS组表现出2项以上RCM特征的受试者比例分别为17.5%（21/120）和51.7%（62/120）,比同一时刻临床评估的阳性率［2.5%（3/120）和12.5%（15/120）］更接近去除SLS 24 h后的临床评估结果34.2%（41/120）和85.0%（102/120）。结论 性别和年龄对0.1%和0.5% SLS诱导的皮肤刺激反应无明显影响;相对临床评估,RCM在刺激反应早期能更加客观准确地评估皮肤反应。     

Artificial disruption of skin barrier prior to irritant patch testing does not improve test design

BACKGROUND: Irritant patch testing is often performed as a 24- or 48-h occlusive patch test with low concentrations of sodium lauryl sulphate (SLS). OBJECTIVES: The aim of this study was to investigate potential ways to shorten this test procedure and obtain precise test results. PATIENTS AND METHODS: Thirty-six healthy volunteers underwent irritant patch testing with different pretreatments (PT) of the test fields. Occlusive test chambers were applied on the upper back with SLS 0.5%, 1%, 2% and 5% in large Finn Chambers(R). The patches were removed after 4 and 24 h, respectively, depending on the concentration used. Test fields were pretreated as follows: PT 0, field without any PT (control); PT 1, prick with lancet; PT 2, prick with test stamp; PT 3, scratch with lancet; PT 4, incision with standardized incision instrument (0.1-0.2 mm depth). Skin reactions were evaluated by transepidermal water loss (TEWL), skin erythema and skin hydration and as well by a visual score (VS) at 4, 24 and 72 h. RESULTS: Our data show an obvious distinction between PT 0-2 and PT 3-4 at all measurement methods. The average TEWL values with PT 3-4 were higher than those with PT 0-2, especially on the 4-h course. This distinction may derive from the shape and size of the skin impairment achieved by PT 3-4, leading to a mechanical barrier disruption. However, SLS may infiltrate directly into deeper skin layers supported by capillarity. Consequently, no or little penetration through the epidermis and interaction with its structures occurs, which is responsible for irritant skin reactions. The SLS dose in the upper skin layers is therefore lower at these PTs. The lower remaining dose of SLS also explains this distinction, especially for the VS. Additionally, there are presumed reactions in deeper layers of the epidermis and dermis at PT 3-4. CONCLUSIONS: In summary, all data suggest a different reaction pattern from the classical irritant response. Therefore, application without any PT seems to be best suited for irritancy skin testing, especially for visual assessment. PTs prior to irritant patch testing have been shown to be unjustifiable.     

The MOAHLFA index of irritant sodium lauryl sulfate reactions: first results of a multicentre study on routine sodium lauryl sulfate patch testing

In a multicentre study of the German Contact Dermatitis Research Group, sodium lauryl sulfate (SLS) 0.25% and 0.5% aq. has been added to routine allergen patch tests to assess its properties as a convenient diagnostic indicator of individual susceptibility to irritation at the time of patch testing. Previous studies indicated that irritant SLS reactivity may be related to individual factors such as age and sex. As these factors are, in turn, among the important predictors of contact allergy to many allergens, e.g. summarized in the 'MOAHLFA index', the impact of the MOAHLFA factors on irritant SLS patch test reactivity, and thus a potential for confounding, was assessed in the 5971 participating patients. As a result of 2 logistic regression analyses with an irritant reaction to 0.25% and 0.5% SLS, respectively, as outcome, male sex was identified as a relatively weak but significant risk factor (OR 1.38), while age 40 years or older was an even weaker risk factor (OR 1.22 and 1.15, respectively). Upon detailed analysis, no clear age gradient could, however, be identified. 1-day exposure time almost halved the odds of an irritant SLS reaction. In conclusion, this type of SLS patch test can be regarded as robust, indicating individual irritability relatively independent from the individual factors analysed here.     

The effect of grenz rays on irritant skin reactions in man

To investigate the effect of grenz rays on irritant contact reactions, eleven healthy volunteers were studied. They were given 3 Gy of grenz rays, once a week for 3 weeks, to a defined area of the back. Twenty-four hours after the last treatment, serial dilution sodium lauryl sulphate patch tests were applied both on the grenz ray treated area and on the untreated control skin. Biopsy specimens were taken from the irritant reactions both from the grenz ray treated area and from the control area and different cell populations in dermis and epidermis were identified by monoclonal antibodies (Leu 2, 3, 4, 7, Leu M1, B1, OKT6). In the grenz ray treated epidermis there was a pronounced reduction of OKT6-positive cells but the composition of the dermal cellular infiltrate did not differ between control and grenz ray treated skin. The assessment of the patch test reactions did reveal a tendency towards weaker reactions in the grenz ray pre-treated skin but this difference was not statistically significant. It is concluded that grenz rays do not have a marked effect on the elicitation of irritant reactions.     

In vivo cytokine profiles in allergic and irritant contact dermatitis

Local cytokine profiles in skin biopsies from allergic and irritant patch test reactions were determined by in vivo immunohistochemistry to differentiate between these 2 clinically identical afflictions especially at the time of final reading in diagnostic patch testing. Biopsies were taken from established allergic persons after specific allergic patch test.-, to epoxy resin (1%) and formaldehyde (1%) and from non-allergic individuals with irritant patch tests to sodium lauryl sulfate (10%) and formaldehyde (8%). At 72 h after application of the agents, significantly enhanced frequencies of dermal infiltrating cells, producing IL-1α, TNF-α. IL-2. and IFN-γ per 100 infiltrating cells in the dermis. were observed in allergic as well us irritant patch test reactions, as compared to normal skin. Significantly higher frequencies of IL- Iα-producing cells were observed in biopsies from epoxy resin (1%) allergen-affected and sodium lauryl sulfate (10%) irritant-affected skin as compared to formaldehyde (1%) allergen-affected skin. In addition, significantly higher frequencies of TNF -α reproducing cells were observed in epoxy resin allergen-affected skin us compared to Formaldehyde (1%) allergen-affected and formaldehyde (8%) irritant affected skin. The allergic and irritant patch test reactions showed similar levels of expression of the Thl cytokines IL-2 and IFN-γ in the dermis. confirmed by probe based detection of IL-2 mRNA and IFN-γ- mRNA, In conclusion, the described similarity shows that allergens and irritants can induce the same profile of IL-la. TNF-α. IL-2. and IFN-γ production, resulting in the near impossibility of discriminating between allergic and irritant contact dermal is at the lime of patch test reading.     

Stratum corneum cytokines and skin irritation response to sodium lauryl sulfate

Little is known about cytokines involved in chronic irritant contact dermatitis. Individual cytokine profiles might explain at least part of the differences in the individual response to irritation. Our objective was to investigate the relation between baseline stratum corneum (SC) cytokine levels and the skin response to a single and a repeated irritation test. This study also aimed to determine changes in SC cytokine levels after repeated irritation. Transepidermal water loss (TEWL) and erythema were measured in 20 volunteers after single 24-hr exposure to 1% sodium lauryl sulfate (SLS), and during and after repeated exposure to 0.1% SLS over a 3-week period. SC cytokine levels were measured from an unexposed skin site and from the repeatedly exposed site. Interleukin (IL)-1alpha decreased by 30% after repeated exposure, while IL-1RA increased 10-fold and IL-8 increased fourfold. Baseline IL-1RA and IL-8 values were predictors of TEWL and erythema after single exposure (r = 0.55-0.61). 6 subjects showed barrier recovery during repeated exposure. Baseline IL-1RA and IL-8 levels are likely to be indicators of higher skin irritability after single exposure to SLS. Barrier repair in some of the subjects might explain the lack of agreement between the TEWL response after single and repeated irritation.     

Value of the cutaneous basophil hypersensitivity (CBH) response for distinguishing weak contact sensitization from irritation reactions in the guinea pig

Numerous studies of the histology of allergic contact dermatitis reactions to potent allergens in guinea pigs and humans have indicated that there is significant tissue infiltration with basophilic leukocytes. In this study we determined whether this histologic finding could be of value in distinguishing weak sensitization reactions from primary irritation, thereby aiding in the predictive identification of weak or moderate contact allergens. Guinea pigs were sensitized by the Buehler test method. Skin reactions were graded 24, 48, and 72 h post-challenge with duplicate patch sites biopsied at the 24- or 72-h grading timepoints. The biopsies were fixed, embedded in glycol methacrylate, thin sectioned, and Giemsa stained. The number of basophils per 400 leukocytes were counted along the upper dermis just below the dermal/epidermal junction. Challenge patch sites from animals sensitized to a relatively low dose of the strong contact allergen, oxazolone, were compared with patch sites from animals challenged only with a strong irritant, sodium lauryl sulfate (SLS). Compared to normal skin (7.5 +/- 1.0 basophils/400 leukocytes +/- SEM) only the oxazolone patch sites showed significant basophil infiltration (36.8 +/- 6.5), despite the fact that the skin reactions to the low oxazolone challenge dose were relatively weak. SLS patch sites showed no basophil infiltration above normal skin levels (4.8 +/- 0.9). Subsequent blinded studies compared weak/moderate presumptive sensitization reactions (as defined by accepted visual skin grading criteria) to various chemicals (citronellal, vanillin, cinnamic aldehyde, and ethylenediamine) to primary irritation reactions to the same chemicals. In each case, low-challenge-dose sensitization sites on previously treated (induced) animals showed mean basophil infiltration (range, 11.9-69.2 basophils/400 leukocytes) significantly greater than higher-dose irritant reactions (range, 1.6-13.3). The range for normal skin was 0.2-10.2 and the range for strong patch reactions to higher concentrations of oxazolone was 59.8-209.3. These data strongly indicate that light-microscopic quantitation of the CBH response can be used to distinguish relatively weak to moderate contact sensitization reactions from primary irritation reactions to the same chemicals.     

Skin irritation thresholds in hairdressers: implications for the development of hand dermatitis

BACKGROUND: Individuals vary in their ability to react to irritants. OBJECTIVES: To observe the development of clinical hand dermatitis and sensitization prospectively in trainee hairdressers and to compare this with their irritant threshold to sodium lauryl sulphate (SLS). METHODS: Subjects were patch tested to a limited series of occupational importance and their irritant threshold to SLS was determined; patch testing was repeated 6 months later and subjects were assessed for hand dermatitis. RESULTS: The development of hand dermatitis was associated with a lower irritant threshold. A similar association was not found for sensitization. CONCLUSIONS: The development of clinical dermatitis in prospectively followed subjects with greater irritant reactivity has not previously been identified. The association of greater irritant reactivity with a proinflammatory cytokine polymorphism may partly explain this. Further development of the irritant threshold test could contribute to the identification of non-atopic subjects at risk of occupational skin disease.     

免疫磁性技术分离提纯酵母样真菌的研究

用包被有羊抗鼠ＩｇＧ的磁珠结合鼠抗白念单抗后，对白念珠菌，类星形念珠菌，类星形念珠菌，热带念珠菌，新生隐球菌，光滑念珠菌菌悬液及白念珠菌与新生隐球菌两菌混悬液进行了分离纯化研究。结果：免疫磁球和白念珠菌，类星形念珠菌结合尤为明显，与热带念珠菌少量结合而不和新生隐球菌，光滑念珠菌结合。     

Invasive and non-invasive studies of the protective action of a silicon-containing cream and its excipient in skin irritation induced by sodium laurylsulfate

The purpose of our study was to evaluate the protective effect of a new silicone-containing barrier-cream (Anthydro) and its vehicle (Anthydro without silicone) in the prevention of cutaneous irritation by detergents. We therefore planned a study in several stages, using an anionic surfactant well known for its irritant properties: sodium laurylsulphate (SLS) in aqueous solution. In a first series of experiments, the protective effect of the Anthydro cream against SLS was studied by invasive methods on guinea-pigs in order to determine histologically the protective effect of the cream when a 10 p. 100 SLS solution was applied on the skin under occlusion during 24 hours (Square chambers, Van der Bend). Typical and reproducible lesions were apparent, and the protected sites were compared with the unprotected sites. In parallel, we used non-invasive methods (conductivity, transepidermal water loss and cutaneous blood flow) to determine in humans the protective effect of Anthydro cream in comparison with unprotected sites after application during 24 hours of patches soaked with a 5 p. 100 SLS solution on the forearms of 13 adult and healthy volunteers (Silver patch tests, Van der Bend). In both experiments the Anthydro cream was effective in reducing the SLS-induced cutaneous irritation. In a second series of experiments, the Anthydro barrier-cream was compared with its "base" (Anthydro without silicone) in terms of effectiveness, following the same experimental procedure (invasive on guinea-pigs, and non-invasive on humans). The base was shown to be effective in protecting against irritation. However, the histological lesions were less intense when the skin was protected by Anthydro than by its vehicle. Concerning the non-invasive methods in humans, no significant statistical differences appeared in the measurement of various parameters between the sites protected by Anthydro and the sites protected by the vehicle. These results lead us to suggest the existence of an essentially mechanical protective effect in which the silicone plays a very small part in terms of effectiveness. These experimental results necessitates further investigations to be extrapolated to occupational conditions without tests performed in industries and well-conducted epidemiological investigations.     

A bioengineering study on the efficacy of a skin protectant lotion in preventing SLS-induced dermatitis

Background/aims: This study evaluated the efficacy of a dimethicone skin protectant lotion against sodium lauryl sulfate (SLS)-induced irritant contact dermatitis (ICD) by clinical visual grading and bioengineering techniques in 12 healthy humans.
Methods: The flexor aspects of both forearms of the subjects were used as test sites. Each test was duplicated to diminish the variations of the test sites. In a random order and a double-blind manner, two test sites were pretreated either with the testing protectant lotion or with its vehicle control prior to contact with SLS. Thirty minutes later, 0.2 ml of 0.5% SLS in a polypropylene chamber was applied to each pretreated site. One additional test site served as a positive control (without lotion), receiving the irritant only. After 24 h of exposure to the irritant, the chambers were removed. The efficacy of protective effect was determined by four parameters: visual scoring (VS), transepidermal water loss (TEWL), skin color ( a * value), and cutaneous blood flow volume (BFV). All test sites were assessed with the parameters daily for 5 days.
Results: The VS data showed a significant decrease on the site pretreated with protectant lotion in comparison with the SLS-only treated site ( P <0.01) and with the site pretreated with control vehicle ( P <0.05) (overall for 5 days). TEWL value was significantly decreased in comparison with the SLS-only treated site ( P =0.02 at day 2; P =0.008 at day 4; P =0.014 at day 5) and with the site pretreated with the control vehicle ( P <0.05) (day 2, 4 and 5). However, the BFV and a * values did not show a statistical difference between protectant lotion, vehicle, and SLS-only treated sites.
Conclusions: This study demonstrated that appropriate dimethicone skin protection products may provide certain benefits from surfactant ICD. The skin protectant lotion may be used to prevent ICD in home or work environments, where skin irritants may induce dermatitis or eczema.     

Correlation between laser Doppler perfusion imaging and visual scoring of patch test sites in subjects with experimentally induced allergic and irritant contact reactions

Purpose: To compare laser Doppler perfusion imaging (LDPI) measurements in experimentally induced allergic contact reactions and irritant contact reactions. The degree of correlation between visual scores and LDPI measurements was also studied.
Methods: Fifteen patients with known contact allergy to nickel or fragrance were patch tested with nickel sulfate 5% pet., fragrance mix 8% pet., sodium lauryl sulfate (SLS) 0.5% pet., SLS 1.0% pet. and two empty control chambers. Visual readings and LDPI measurements were taken at 0, 48 and 96 h.
Results: There was a positive correlation between visual scores and LDPI measurement in the nickel sulfate and fragrance mix patch test sites. However, no correlation between visual scores and LDPI measurements was seen in the SLS 0.5% and SLS 1.0% patch test sites. There was no significant difference ( P =0.125) in LDPI measurements between contact-allergic reactions and contact-irritant reactions.
Conclusion: LDPI correlates with visual scoring in contact-allergic reactions, but not in irritant reactions. LDPI is not useful in distinguishing between allergic and irritant reactions.     

Allergic contact dermatitis from ophthalmic products: can pre‐treatment with sodium lauryl sulfate increase patch test sensitivity?

In patients suspected of allergic contact dermatitis because of topical ophthalmic medicaments, patch tests performed with patients' own products are often negative. The irritant anionic surfactant sodium lauryl sulfate (SLS) may alter the stratum corneum and increase antigen penetration. Pre-treatment of the skin with SLS 0.5% for 24 h was performed in the sites of patch tests with patients' own products in 15 selected patients. In patients previously negative to their own products tested with conventional patch tests, SLS pre-treatment showed 6 new relevant positive reactions and induced a stronger positive reaction in 1 patient. SLS pre-treatment could be proposed as an alternative promising method, which may increase sensitivity of patch tests with patients' own products.