Matrix remodelling and MMP expression/activation are associated with hidradenitis suppurativa skin inflammation

Hidradenitis suppurativa/acne inversa (HS) is a chronic, inflammatory, recurrent, debilitating skin disease of the hair follicle, associated with considerable tissue remodelling. Although abnormal cytokine expression was detected both in perilesional and in uninvolved skin, up to now there is no model allowing a better understanding of the implicit inflammatory mechanisms in HS. The aim of this study was to investigate the inflammatory response in HS skin by mean of an ex vivo model culture. To that purpose, nine skin biopsy specimens from patients suffering from HS and controls were cultured up to 4 days. Microscopy imaging investigations showed variations of collagen I and III organization, and an increase in elastin fibres fragmentation in HS skin after 4 days of culture. The HS matrix structure remodelling was associated with high level of MMP‐2 and MMP‐9 in HS lesional skin. After 4 days of culture, the MMP expression in HS perilesional skin reached the level observed in HS lesional skin. Concomitantly, an increase in IL‐1β concentration was observed in all skin samples after 4 days of culture, although IL‐1β concentrations remained significantly higher in HS lesional skin as compared with control skin. Meanwhile, neither IL‐17 concentrations nor the inflammasome components NLRP3 and caspase‐1 varied. Thus, our HS skin model culture showed that MMP‐induced matrix alteration could participate in HS inflammation by releasing biological active peptides and inflammatory factors from the extracellular matrix (ECM), and open new opportunities to investigate the regulation of the inflammatory mechanism associated with HS.     

IL‐26 in allergic contact dermatitis: Resource in a state of readiness

In this study, we investigated the role of IL‐26 in allergic contact dermatitis (ACD), highlighting its’ contribute in the cytotoxic mechanism responsible for the tissue injury. IL‐26 is a signature Th17 cytokine, and immune cells are its predominant sources. Recently, it has shown that Th17 cell‐derived‐IL‐26 functions like an antimicrobial peptide. Here, we hypothesized that IL‐26 could be involved in cytotoxicity mechanism that underlies ACD. Indeed, we have attributed a role to IL‐26 in this context, through PBMC cytotoxicity assays vs HaCat. To demonstrate that IL‐26 was effectively involved in this activity, we performed the assay using transfected ACD PBMCs by siRNA for IL‐26. Indeed, we demonstrated that these cells were less able to kill keratinocytes compared with ACD PBMCs (P < .01). In conclusion, our findings support the idea that this emergent cytokine, IL‐26, is implicated in the killing mechanisms of KC observed during ACD.     

Severe hidradenitis suppurativa responding to treatment with secukinumab: a case report

An inappropriate immunological response to an unknown antigen has been suggested to play a role in the pathogenesis of hidradenitis suppurativa (HS). Studies have identified elevated levels of several proinflammatory cytokines, including interleukin (IL)‐17A and tumour necrosis factor‐α, nominating these as possible therapeutic targets.¹ Secukinumab is an IL‐17A monoclonal antibody, which binds to IL‐17A and inhibits the cytokine interaction with the IL‐17 receptors, inhibiting the inflammatory cascade. Here we report a case of a 47‐year‐old man, with Hurley stage III lesions on the neck, axillae, breasts, genital skin and buttocks, who had experienced only temporary benefit from different medical treatments over several years. After 12 weeks of treatment with secukinumab, the number of lesions reported by the patient within the period of the last 4 weeks was reduced from 23 to seven, his pain visual analogue scale (VAS) score was reduced from 5 to 3 and pain/utility/handicap VAS score was reduced from 7 to 4. These results may be taken to imply that IL‐17 blockade could provide a possible therapeutic approach in the treatment of HS.     

Evidence that a neutrophil–keratinocyte crosstalk is an early target of IL‐17A inhibition in psoriasis

The response of psoriasis to antibodies targeting the interleukin (IL)‐23/IL‐17A pathway suggests a prominent role of T‐helper type‐17 (Th17) cells in this disease. We examined the clinical and immunological response patterns of 100 subjects with moderate‐to‐severe psoriasis receiving 3 different intravenous dosing regimens of the anti‐IL‐17A antibody secukinumab (1 × 3 mg/kg or 1 × 10 mg/kg on Day 1, or 3 × 10 mg/kg on Days 1, 15 and 29) or placebo in a phase 2 trial. Baseline biopsies revealed typical features of active psoriasis, including epidermal accumulation of neutrophils and formation of microabscesses in >60% of cases. Neutrophils were the numerically largest fraction of infiltrating cells containing IL‐17 and may store the cytokine preformed, as IL‐17A mRNA was not detectable in neutrophils isolated from active plaques. Significant clinical responses to secukinumab were observed 2 weeks after a single infusion, associated with extensive clearance of cutaneous neutrophils parallel to the normalization of keratinocyte abnormalities and reduction of IL‐17‐inducible neutrophil chemoattractants (e.g. CXCL1, CXCL8); effects on numbers of T cells and CD11c‐positive dendritic cells were more delayed. Histological and immunological improvements were generally dose dependent and not observed in the placebo group. In the lowest‐dose group, a recurrence of neutrophils was seen in some subjects at Week 12; these subjects relapsed faster than those without microabscesses. Our findings are indicative of a neutrophil–keratinocyte axis in psoriasis that may involve neutrophil‐derived IL‐17 and is an early target of IL‐17A‐directed therapies such as secukinumab.     

Interleukin‐10 secretion from CD14+ peripheral blood mononuclear cells is downregulated in patients with acne vulgaris

Background Acne is a common chronic inflammatory dermatosis of the pilosebaceous unit. It is characterized by seborrhoea, comedone formation and an inflammatory response consistent with defective cellular immunity to Propionibacterium acnes. Objectives The objective of this study was to investigate the immune reactivity of patients with acne compared with healthy controls by examining the response of peripheral blood mononuclear cells (PBMCs) to stimulation with P. acnes. Particular focus was placed upon measuring the production of interleukin (IL)‐10, which has an established immunoregulatory role. Patients and methods Venous blood was collected from 47 patients with acne and 40 age‐ and sex‐matched healthy controls with no prior history of acne. PBMCs were cultured and their cytokine response to P. acnes investigated. Results Proinflammatory IL‐8 and tumour necrosis factor (TNF)‐α secretion from PBMCs was higher in patients with acne when stimulated with P. acnes. In contrast, a statistically significant reduction in PBMC secretion of anti‐inflammatory IL‐10 in patients with acne was identified. The impaired production of IL‐10 by PBMCs from patients with acne was confined to CD14+ cells presumed to be monocytes. The ability of CD14 cells from patients with acne to phagocytose P. acnes bacteria was also observed to be defective but the addition of exogenous IL‐10 to PBMC cultures restored phagocytic activity. Conclusions These data suggest that patients with acne have a proinflammatory cytokine milieu and crucially are unable to contain early inflammatory changes due to a specific defect in immunosurveillance, namely low monocyte IL‐10 production. Our observations raise the possibility that acne therapeutics might profitably target IL‐10 both as a regulator of proinflammatory cytokines and in augmenting the CD14+ cell phagocytic response.     

IL‐33 is secreted by psoriatic keratinocytes and induces pro‐inflammatory cytokines via keratinocyte and mast cell activation

IL‐33 is a novel pro‐inflammatory cytokine and ligand for the orphan receptor ST2. Although originally defined as an inducer of Th2‐mediated responses, IL‐33 was recently found to be involved in arthritis, a Th1/Th17‐mediated disease. Here, we assessed the ability of IL‐33 to promote inflammation via mast cells (MCs) and keratinocytes (KCs) activation in psoriasis. IL‐33 resulted elevated in the skin but not in the serum of psoriasis patients. IL‐33 was secreted by psoriasis KCs and HaCaT cells after TNF‐α stimulation. In HMC‐1, TNF‐α, but not IL‐17, could induce a robust increase in IL‐33 expression. In HaCaT cells, TNF‐α was able to induce IL‐6, MCP‐1 and VEGF, and the addition of IL‐33 reinforced these increases. TNF‐α + IL‐33 combination showed similar results in primary KCs and ex vivo skin organ culture. In conclusion, our study suggests that IL‐33 may be involved in psoriasis biology via MCs and KCs.     

Longitudinal observational study of hidradenitis suppurativa: impact of surgical intervention with adjunctive biologic therapy

Background

Hidradenitis supppurativa (HS) is a chronic inflammatory disease of the apocrine sweat glands affecting 1–4% of the population. While surgical excision is a mainstay of therapy, lesions often recur. Biologic therapies, including tumor necrosis factor‐α and IL‐12/23 inhibitors, are effective for mild to moderate HS. However, longitudinal studies investigating biologic therapy in conjunction with surgery are limited. The purpose of this analysis was to investigate impact of surgery and biologic therapy on HS disease activity.

Methods

Data from 68 HS patients were analyzed. Outcome measures included hidradenitis suppurativa Sartorius Score (HSS), active nodule (AN) count, Hurley stage, and probability of achieving 75% reduction in active nodule count (AN75).

Results

Mean age was 40 ± 14 years; 66% were female and 72% were African American. Mean disease duration was 10 years, and Hurley stage III disease was seen in 63% of patients. Patients who received biologics had a larger drop in HSS and AN count than those who never received biologics (P = 0.002). Biologic treatment was associated with average reduction in 22 (15–29) HSS points (P < 0.0001). The effect of biologics was greater in patients who also underwent surgery (P = 0.013). Timing of biologics relative to surgery did not impact efficacy. Patients who received HS surgery with biologic therapy were most likely to achieve the AN75 (P = 0.017).

Conclusions

In this diverse cohort of patients with severe HS, biologic therapy was associated with a more rapid decline in disease activity, with the greatest effect in patients who also underwent HS surgery.     

Case of allergic contact dermatitis due to 1,3‐butylene glycol

1,3‐Butylene glycol (1,3‐BG) is widely used in cosmetics, including low‐irritant skin care products and topical medicaments, as an excellent and low‐irritation humectant. We report a case of allergic contact dermatitis caused by 1,3‐BG. A 28‐year‐old woman suffered from an itchy erythematous eruption on her face. By 2 days of closed patch testing, her own cosmetics and many of the hypo‐irritant skin care products showed positive results. A second patch testing showed positive reaction to 1,3‐BG (1% and 5%). 1,3‐BG was a common component in most of the products that had elicited a positive reaction in the first patch testing. Although allergic contact dermatitis due to 1,3‐BG is not so common, we have to consider 1,3‐BG as a possible contact allergen in the patients presenting with allergic contact dermatitis due to various cosmetics.     

Elevated levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-10 in hidradenitis suppurativa skin: a rationale for targeting TNF-α and IL-1β

Background The pathogenesis of hidradenitis suppurativa (HS) is largely unknown and the disease is difficult to treat. Patients are in high need of an effective treatment. Although it is not known whether the levels of tumour necrosis factor (TNF)‐α are aberrant in HS skin, anti‐TNF‐α biologics are used, with variable clinical efficacy. Objectives To determine the cytokine profile in lesional and perilesional HS skin. Methods We cultured 20 lesional and 10 normal‐appearing perilesional HS skin samples, seven psoriasis and six healthy control skin samples in a transwell culture system. Two distinct cytokine bead arrays were used to measure the spectrum of inflammatory cytokines in the culture supernatant. Results from HS skin samples were compared with those of healthy and psoriasis skin. Results The proinflammatory cytokines interleukin (IL)‐1β and TNF‐α as well as the anti‐inflammatory cytokine IL‐10 were significantly elevated in HS skin. Elevated levels of these cytokines were also found in perilesional HS skin. Fold increases relative to control skin of IL‐1β, TNF‐α and IL‐10 in HS were 31, 5 and 34, compared with psoriasis: 4, 1 and 2, respectively. Levels of all three cytokines showed a trend towards a positive correlation with disease severity. IL‐2, IL‐4, IL‐5 and interferon‐γ were hardly detectable in HS or healthy control skin. Conclusions This study shows for the first time that IL‐1β, TNF‐α and IL‐10 levels are elevated in HS skin. These data provide a rationale for therapies with biologics targeting cytokines such as TNF‐α and IL‐1.     

Para‐phenylenediamine‐specific lymphocyte activation test: a sensitive in vitro assay to detect para‐phenylenediamine sensitization in patients with severe allergic reactions

Please cite this paper as: Para‐phenylenediamine‐specific lymphocyte activation test: a sensitive in vitro assay to detect para‐phenylenediamine sensitization in patients with severe allergic reactions. Experimental Dermatology 2010; 19: 435–441. Abstract: Patients sensitized to para‐phenylenediamine (PPD) by semi‐permanent tattoos increasingly develop threatening allergic reactions in response to black hair dye. The gold standard to diagnose allergic contact dermatitis is to perform epicutaneous patch tests, however, iatrogenic sensitizations and severe patch test reactions to PPD have been described, the latter especially in patients with severe allergic reactions. We examined nine patients with severe allergic reactions in response to permanent hair dyes. Patch tests using the standard concentration of 1% or 0.5% PPD resulted in severe and sometimes even bullous reactions in all patients responsive to PPD. Titration revealed that at 1% of the standard concentration (0.01% PPD), patch test sensitivity decreased and only 50% of patients responded. Consequently, we established an in vitro assay to diagnose PPD allergy. Freshly isolated peripheral blood mononuclear cells (PBMC) were cultured with titrated concentrations of PPD with or without IL‐2 supplementation, and cell proliferation was determined by [3H]‐thymidine incorporation. Lymphocyte activation test (LAT ) detected PBMC cell proliferation specific to PPD, with at least 3.5‐fold increase in [3H]‐thymidine uptake in all PPD allergic patients. Most importantly, PPD – LAT without IL‐2 supplementation remained negative in three out of eight PPD allergic patients. Thus, PPD‐LAT with IL‐2 supplementation demonstrated a sensitivity of 100%, remained unresponsive in controls not sensitized to PPD, and in one patient sensitive to other p‐amino compounds. These data demonstrate that LAT with PPD can be used to detect PPD sensitization as a possible alternative to patch testing at least in patients with severe allergic reactions to PPD.     

Association between oral lichenoid reactions and amalgam restorations

Background The aim of this study was to perform a clinical assessment of the association between oral lichenoid reactions (OLR) and amalgam restorations and to determine the salivary concentrations of interleukin‐6 (IL‐6) and IL‐8 before and after replacement of the amalgam restorations. Methods The study included 20 patients with OLR and 20 healthy volunteers, who were examined between 2001 and 2005 at the Oral Medicine Unit of the Medical Faculty University of Rijeka. All patients were skin patch tested by an experienced physician. Saliva samples were collected, prepared and analysed for IL‐6 and IL‐8 concentrations using enzyme‐linked immunosorbent assay. Results Sixteen out of 20 patch‐tested patients showed a sensitization to inorganic mercury or amalgam. Total replacement of all amalgam fillings was carried out on 20 patients with fillings based on composite resin, gold, porcelain or a combination of these. Sixteen out of 20 patients showed complete healing of OLR; three patients had marked improvement, whereas one patient showed no improvement. Levels of IL‐6 detected before replacement were significantly higher than IL‐6 levels following the replacement (P = 0.003). The IL‐8 levels measured before replacement procedure were significantly higher than the IL‐8 levels after replacement of the fillings (P < 0.001). Conclusions On the basis of clinical observations, restorative therapy resulted in tissue healing. Following the replacement of amalgam fillings with fillings based on other restorative materials, levels of both IL‐6 and IL‐8 shifted towards normal, as measured in healthy subjects.     

Adalimumab (antitumour necrosis factor-α) treatment of hidradenitis suppurativa ameliorates skin inflammation: an in situ and ex vivo study

Background Hidradenitis suppurativa (HS) is a difficult‐to‐manage disease. Randomized controlled trials with antitumour necrosis factor (TNF)‐α biologics have been conducted and in most studies disease activity was reduced. However, the mechanism of action in HS skin is so far unknown. Objectives To assess whether anti‐TNF‐α treatment affects in situ cytokine production and frequency of inflammatory cell populations in HS lesional skin. Methods Nine patients with HS, participating in a larger placebo‐controlled, double‐blind phase IIb clinical trial on the efficacy and safety of adalimumab in patients with moderate to severe HS (M10‐467), were randomized and treated for 16 weeks. In a mechanism‐of‐action substudy, biopsies were obtained at fixed time points pre‐ and post‐treatment. One part of the biopsy was cultured for 24 h for cytokine release in the culture medium, while another part was used for in situ analysis. Results Secretion of cytokines, including interleukin (IL)‐1β, CXCL9 [monokine induced by interferon‐γ (MIG)], IL‐10, IL‐11, B‐lymphocyte chemoattractant (BLC) and IL‐17A, was significantly elevated in HS. Adalimumab treatment was associated with decreased production of cytokines in HS skin, especially IL‐1β, CXCL9 (MIG) and BLC. Treatment significantly reduced the number of CD11c+, CD14+ and CD68+ cells in HS lesional skin. The numbers of CD3+ and CD4+ T cells, and CD20+ and CD138+ B cells were also reduced by adalimumab treatment. Conclusions Adalimumab treatment inhibits important cytokines and inflammatory cell numbers in lesional HS skin, especially levels of IL‐1β and numbers of inflammatory CD11c+ dendritic cells.     

Nicotinamide downregulates gene expression of interleukin‐6, interleukin‐10, monocyte chemoattractant protein‐1, and tumour necrosis factor‐α gene expression in HaCaT keratinocytes after ultraviolet B irradiation

Ultraviolet (UV) radiation has profound effects on human skin, causing sunburn, inflammation, cellular‐tissue injury, cell death, and skin cancer. Most of these effects are mediated by a number of cytokines produced by keratinocytes. In this study we investigated whether nicotinamide (NCT), the amide form of vitamin B3, might have a protective function in reducing the expression of interleukin (IL)‐1β, IL‐6, IL‐8, IL‐10, monocyte chemoattractant protein (MCP)‐1 and tumour necrosis factor (TNF)‐α in UV‐irradiated keratinocytes. HaCaT cells were treated with UVB in the presence or absence of NCT, and cytokine mRNA levels were examined by quantitative real‐time PCR. NCT significantly downregulated IL‐6, IL‐10, MCP‐1 and TNF‐α mRNA expression, whereas it did not exert any significant effect on IL‐1β or IL‐8 expression. Because of its ability to decrease these cytokine mediators after UV exposure, NCT is a possible therapy to improve or prevent conditions induced or aggravated by UV light.     

Reduced expression of microtubule-associated protein 1 light chain 3 in hypertrophic scars

Autophagy is a tightly regulated physiological process essential for cellular maintenance, differentiation, development, and homeostasis. Aberration of this process associates with the pathogeneses of several diseases in mammals. Hypertrophic scar (HS) is characterized by an abundance of collagenous tissue with hypercellularity. However, the molecular mechanism in HS formation is poorly understood. We compared the autophagic capacity in HS and its normal skin (NS) counterparts and explored the molecular mechanism of autophagy during the formation of HS. Microtubule-associated protein 1 light chain 3 (LC3) proteins in HS and NS were detected by immunohistochemistry, Western blot and quantitative real-time PCR (qPCR). The data showed that LC3 positive staining in HS was less intensive relative to NS group (p < 0.05). Three forms of LC3, with molecular weights of about 19 kDa (proLC3), 18 kDa (LC3-I) and 16 kDa (LC3-II), respectively, expressed in NS by Western blot. In contrast, only proLC3 expressed while both LC3-I and LC3-II were significantly downregulated in HS. The protein level of beclin 1 in HS was significantly lower compared with NS (p < 0.05). LC3 and beclin 1 mRNA levels in HS were significantly lower than that in NS (p < 0.05). These results suggest that the generation of LC3-I and LC3-II are interrupted in HS, and that the resultant decrease of autophagic capacity may associate with the pathogenesis of HS.     

IL6Rα function in myeloid cells modulates the inflammatory response during irritant contact dermatitis

Irritant contact dermatitis (ICD) is characterized by epidermal hyperplasia, infiltration of leucocytes into lesional skin and inflammatory cytokine release. The cellular infiltrate during ICD comprises primarily cells of the myeloid lineage. Our group has previously shown that the cytokine IL‐6 confers a protective effect to lesional skin during ICD. How IL‐6Rα function in myeloid cells is involved in the inflammatory response during ICD is, however, unknown. In the present study, utilizing a chemical model of ICD, it is shown that mice with a myeloid‐specific knockout of the IL‐6Rα (IL‐6Rα^Δmyeloid) display an exaggerated inflammatory response to benzalkonium chloride (BKC) and Jet propellant‐8 (JP8) fuel, two well‐characterized irritants relative to littermate control. Results from immunohistochemical and flow cytometric analyses revealed that IL‐6Rα^Δmyeloid mouse skin displayed increased epidermal hyperplasia and inflammatory monocyte influx into lesional skin but lower numbers of resident macrophages relative to littermate controls after irritant exposure. Multiplex immunoassay revealed significantly higher levels of pro‐inflammatory cytokines IL‐1α and TNF‐α, but reduced expression of chemokine proteins including CCL2‐5, CCL7, CCL11, CXCL1 and CXCL10 in IL‐6Rα^Δmyeloid mouse skin relative to littermate control following irritant exposure. These results highlight a previously unknown role of IL‐6Rα function in myeloid cells in modulating the inflammatory response and myeloid population dynamics during ICD.     

Distinct age‐matched serum biomarker profiles in patients with cutaneous T‐cell lymphoma

Immunological functions decline with age. Because MS/SzS predominately affects the elderly, it is important to distinguish age‐related from cancer‐specific changes. Also, MF and SzS are malignancies of CD4⁺ T‐lymphocytes, further compromising an immune state of the patients. The objectives of this study were to distinguish disease‐specific immunological deterioration by performing comparative age ‐ matched Luminex multiplex assessment of 34 serum biomarkers between patients with MF/SzS, HIV‐infected individuals and normal controls. Controlling for age, expression level appears to significantly differ between patients with MF/SzS and controls for the following biomarkers: G‐CSF, IL‐5, MIP‐1β, TNF‐α, VEGF, EOTAXIN, IL‐8, IL‐12, IL‐2R, IP10, MCP‐1, MIG, TNFR1 and TNFR2 (P < 0.05), while others showed normal age‐related changes. Interestingly, cluster analysis placed MF/SzS profiles closer to HIV. This further underscores an immunologically compromised state of patients with MF/SzS and suggests its potential self‐perpetuating role in disease progression.     

Interleukin‐36 in hidradenitis suppurativa: evidence for a distinctive proinflammatory role and a key factor in the development of an inflammatory loop

Scientists from Germany investigated whether a cytokine called interleukin‐36 (IL‐36) might be important in hidradenitis suppurativa (HS), a chronic, painful, disfiguring and offensive‐smelling pustular skin disease that affects the armpits, groins, buttocks and breasts. A cytokine is a molecule produced by one cell that switches on other cells in some way ‐ for example, activating immune system cells to home in on sites of damage, including damage from infection. This is a complex chain reaction or loop. If cytokines are produced when they should not be produced, instead of the immune system repairing damage or combating infection as it should, inappropriate inflammation such as that seen in HS can result. This study of skin samples from 15 patients with moderately severe or severe HS found elevated levels of all three subtypes of IL‐36, mainly in the cells called keratinocytes: subtype IL‐36α particularly in affected skin, IL‐36β in skin around affected skin, and IL‐36γ in both. It also demonstrated an imbalance of cytokines IL‐37 and ‐38, which oppose the action of IL‐36. These findings suggest that the immune system plays an important role in the development of HS. They fit the theory that high IL‐36 levels kick off a chain reaction (which includes other interleukins and a particular type of white blood cell called a T‐helper cell) that results in inflammation and sufficient white blood cells to produce the pus that is a major feature of the condition.     

IL1A‐889 C/T gene polymorphism in irritant contact dermatitis

Background Upon skin contact to irritants, interleukin‐1 alpha (IL‐1α) is released in the stratum corneum as a primary step of skin inflammation. Variations in the IL‐1A gene have been shown to alter the expression of IL‐1α. This may influence the susceptibility to skin inflammation and the development of irritant contact dermatitis (ICD). Objective To determine effects of an IL1A‐889 C/T polymorphism in view of susceptibility to develop irritant contact dermatitis. Methods In a case–control study, 478 Caucasian patients with occupational ICD of the hands were genotyped for an IL1A‐889 C/T polymorphism. Results were compared to 393 apprentices from the same high risk occupations (controls). Results Trends of a protective effect of the C→T transition at position IL1A‐889 were seen (OR = 0.81; 95% CI: 0.65–1.00). The genotype distribution for IL1A‐889 was 52.2% wild type (C/C), 39.2% heterozygous (C/T) and 8.6% homozygous for variant allele (T/T) in patients and 46.0%, 42.7% and 11.4% in controls. Subgroup analysis, which took into account atopy status and exposure, did not reveal a significant effect of this polymorphism for an aberrant risk to acquire for ICD. Conclusion Our study indicates a possible protective effect of the IL1A‐889 C/T polymorphism regarding the development of ICD.     

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.