The role of superantigens in human diseases: therapeutic implications for the treatment of skin diseases

Ixekizumab for the treatment of pediatric patients with moderate to severe plaque psoriasis

Introduction: Ixekizumab (IXE), a high affinity humanized monoclonal antibody that selectively targets interleukin-17A, is approved in the United States (US) and the European Union (EU) for pediatric patients with moderate to severe plaque psoriasis. This review summarizes ixekizumab use in the phase 3, randomized, double-blind, placebo-controlled study in pediatric patients with moderate to severe plaque psoriasis and provides some clinical pearls we have learned after using the drug in the pediatric population for the past 3 years.Areas covered: Review of IXORA-PEDS trial data, general literature review pertaining to the systemic treatment of pediatric psoriasis as well as our clinical experience with IXEExpert opinion: IXE is the only IL17 antagonist for pediatric psoriasis and is a welcome addition to our armamentarium.

Therapeutic Effects of Synthetic Antimicrobial Peptides, TRAIL and NRP1 Blocking Peptides in Psoriatic Keratinocytes

Psoriasis is a chronic, recurrent, heterogeneous, cutaneous inflammatory skin disease for which there is no cure. It affects approximately 7.5 million people in the United States. Currently, several biologic agents that target different molecules implicated in the pathogenic processes of psoriasis are being assessed in diverse clinical studies. However, relapse usually occurs within weeks or months, meaning there is currently no cure for psoriasis. Therefore, recent studies have discovered diverse new potential treatments for psoriasis: inhibitors of bacteria such as Staphylococcus aureus, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and neuropilin 1 (NRP1). A promising approach that has recently been described involves modifying antimicrobial peptides to develop new cutaneous anti-bacterial agents that target inflammatory skin disease induced by Staphylococcus. Increased expression of TRAIL and its death receptors DR4 and DR5 has been implicated in the pathogenesis of plaque psoriasis. In addition, TRAIL has the ability to inhibit angiogenesis by inducing endothelial cell death and by negative regulation of VEGF-induced angiogenesis via caspase-8-mediated enzymatic and non-enzymatic functions. Since NRP1 regulates angiogenesis induced by multiple signals, including VEGF, ECM and semaphorins, and also initiates proliferation of keratinocytes through NF-κB signaling pathway in involved psoriatic skin, targeting NRP1 pathways may offer numerous windows for intervention in psoriasis. In this review, we will focus on the current knowledge about the emerging role of synthetic antimicrobial peptides, TRAIL and NRP1 blocking peptides in the pathogenesis and treatment of psoriasis.

The immunopathogenesis of staphylococcal skin infections - A review

Staphylococcus aureus and S. pseudintermedius are the major causes of bacterial skin disease in humans and dogs. These organisms can exist as commensals on the skin, but they can also cause severe or even devastating infections. The immune system has evolved mechanisms to deal with pathogenic microorganisms and has strategies to combat bacteria of this type. What emerges is a delicate "peace" between the opposing sides, but this balance can be disrupted leading to a full blown "war". In the ferocious battle that ensues, both sides attempt to get the upper hand, using strategies that are comparable to those used by modern day armies. In this review article, the complex interactions between the immune system and the organisms are described using such military analogies. The process is described in a sequential manner, starting with the invasion itself, and progressing to the eventual battlezone in which there are heavy casualties on both sides. By the end, the appearance of a simple pustule on the skin surface will take on a whole new meaning.

Leukocyte Infiltration and mRNA Expression of IL-20, IL-8 and TNF-R p60 in Psoriatic Skin is Driven by TNF-α

Anti-TNF-α therapy with a chimeric monoclonal antibody (Infliximab, Remicade®) has been shown to be highly effective in the treatment of skin lesions as well as arthritis in patients with psoriatic arthritis. In this study we investigated the molecular consequences of the in vivo TNF-α blockade with infliximab in psoriatic skin lesions of 6 patients with severe psoriatic arthritis. Biopsies from lesional and non-lesional skin were taken before and 10 weeks after the initiation of treatment. Immunohistochemistry and semiquantative RT-PCR were performed focusing on proinflammatory gene products. Immunohistochemistry, after three infusions, revealed a marked decrease in the expression of TNF-α, HLA-DR, CD3, CD15, ICAM-1 and LFA-1 positive cells. By semiquantitative RT-PCR, we analysed mRNA expression of IL-8, IL-20, TNF-R (TNF-R p60 and TNF-R p80), IL-1R I and IL-1R II, as well as ICAM-2. Before therapy, m-RNA for IL-8, IL-20, TNF-R p60, TNF-R p80, IL-1R II and ICAM-2 were detected in lesional skin. mRNA expression of IL-8 and IL-20 completely disappeared and mRNA expression of TNF-R p60 was reduced after therapy. This effect on IL-8 expression was paralleled by a decreased infiltration of leukocytes in psoriatic skin. These data suggest that the clinical response of anti-TNF-α therapy in patients with psoriasis or psoriatic arthritis may be, at least in part, caused by the inhibition of the production of proinflammatory cytokines and by the decreased expression of adhesion molecules with the consequence of an impaired migration of proinflammatory cells into the inflamed tissue. These data further support a critical role for TNF-α in the pathology of psoriasis.

Sensitization rates of causative allergens for dogs with atopic dermatitis: detection of canine allergen-specific IgE

Allergen-specific IgE serology tests became commercially available in the 1980s. Since then these tests have been widely used to diagnose and treat allergic skin diseases. However, the relationship between a positive reaction and disease occurrence has been controversial. The purpose of this study was to evaluate allergens using a serologic allergy test in dogs with atopic dermatitis (AD). Dogs clinically diagnosed with AD (n = 101) were tested using an allergen-specific IgE immunoassay. Among the total 92 environmental and food allergens, house dust and house dust mites were the most common. Several allergens including airborne pollens and molds produced positive reactions, and which was considered increasing allergens relating to the climate changes. The presence of antibodies against staphylococci and Malassezia in cases of canine AD was warranted in this study. Additionally, strong (chicken, turkey, brown rice, brewer's yeast, and soybean) and weakly (rabbit, vension, duck, and tuna) positive reactions to food allergens could be used for avoidance and limited-allergen trials.

Innate and adaptive immune responses against Staphylococcus aureus skin infections

Staphylococcus aureus is an important human pathogen that is responsible for the vast majority of bacterial skin and soft tissue infections in humans. S. aureus can also become more invasive and cause life-threatening infections such as bacteremia, pneumonia, abscesses of various organs, meningitis, osteomyelitis, endocarditis, and sepsis. These infections represent a major public health threat due to the enormous numbers of these infections and the widespread emergence of methicillin-resistant S. aureus (MRSA) strains. MSRA is endemic in hospitals worldwide and is rapidly spreading throughout the normal human population in the community. The increasing frequency of MRSA infections has complicated treatment as these strains are more virulent and are increasingly becoming resistant to multiple different classes of antibiotics. The important role of the immune response against S. aureus infections cannot be overemphasized as humans with certain genetic and acquired immunodeficiency disorders are at an increased risk for infection. Understanding the cutaneous immune responses against S. aureus is essential as most of these infections occur or originate from a site of infection or colonization of the skin and mucosa. This review will summarize the innate immune responses against S. aureus skin infections, including antimicrobial peptides that have direct antimicrobial activity against S. aureus as well as pattern recognition receptors and proinflammatory cytokines that promote neutrophil abscess formation in the skin, which is required for bacterial clearance. Finally, we will discuss the recent discoveries involving IL-17-mediated responses, which provide a key link between cutaneous innate and adaptive immune responses against S. aureus skin infections.

Staphylococcal enterotoxin A: a candidate for the amplification of physiological immunoregulatory responses in the gut

Staphylococcal enterotoxin A (SEA) is one of the bacterial products tested for modulation of unwanted immune responses. Of all the staphylococcal enterotoxins, SEA is the most potent stimulator of T cells. When administered orally, SEA acts as a superantigen (SA), producing unspecific stimulation of intra-epithelial lymphocytes (IELs) in the intestinal mucosa. This stimulation results in amplification of the normal local immunologic responses, which are mainly regulatory. This amplification is based on increased local production of IFN-γ by IELs, which acts on the nearby enterocytes. As a result, the enterocytes produce large amounts of tolerosomes, cellular corpuscles which detach themselves from the basal poles of the enterocytes and contain antigenic peptides that are conditioned to be interpreted as tolerogenic by the gut immune system. Tolerosomes are physiologically produced as a response to dietary peptides; it is already known that enterocytes posses the molecular mechanisms for processing peptides in a similar manner to lymphocytes. The fate of tolerosomes is not precisely known, but it seems that they merge with intestinal dendritic cells, conveying to them the information that orally administered peptides must be interpreted as tolerogens. SEA can stimulate this mechanism, thus favoring the development of tolerance to peptides/proteins administered subsequently via the oral route. This characteristic of SEA might be useful in therapy for regulating immune responses. The present paper reviews the current status of research regarding the impact of SEA on the enteric immune system and its potential use in the treatment of allergic and autoimmune diseases.

Tacrolimus: 10 years of successful clinical application

Tacrolimus (FK506) is the first drug from the new class of drugs - calcineurin inhibitors. It has a great potential and can change the current approaches to treatment of different dermatoses. Topical forms of Tacrolimus are activated due to the effect on T-lymphocyte signal transduction, and they also inhibit gene transcription. As a result, the T-cell response to antigens is alleviated. Percutaneous absorption of Tacrolimus in affection foci is higher than in healthy skin. Due to this a smaller amount of the drug is absorbed by the skin as long as the skin is healed. Systemic absorption of Tacrolimus is low in the course of treatment. The maximum clinical experience has been gained in the field of applying Tacrolimus for treatment of atopic dermatitis. In a number of clinical studies, 0.03-0.3% Tacrolimus ointment efficiently reduced the severity of symptoms and course of atopic dermatitis in adults and children. Moreover, topical treatment with Tacrolimus did not involve any substantial toxic effects. The patients most often complained of local irritations in the area where the ointment was applied, which were transient by nature and did not demand the drug withdrawal. Today Tacrolimus is a valuable and safer alternative to glucocorticosteroids for treatment of atopic dermatitis. It can also be used for treating other dermatoses, which demands additional all-round examination.

Upper gastrointestinal findings and detection of Helicobacter pylori in patients with oral lichen planus

BACKGROUND

Lichen planus (LP) is a mucocutaneous disease of unknown aetiology, which may involve the gastrointestinal (GI) mucosa. The association of Helicobacter pylori with LP has been a subject of debate.

AIM

To investigate upper GI findings and the presence of H. pylori in GI mucosa and oral LP (OLP).

METHODS

Oral biopsies from 20 patients with erosive OLP and 20 with non-erosive OLP were investigated for the presence of H. pylori by histopathological examination and PCR. Upper GI endoscopy and GI mucosal biopsies were examined for LP lesions and/or H. pylori.

RESULTS

The endoscopic findings of both groups were oesophagitis, antral gastritis and duodenitis. No LP or LP-like changes were found in the upper GI mucosa. H. pylori was found by histopathological examination in the gastric mucosa of 18 patients (45%), with equal distribution in both the control and study groups. Positive PCR results were obtained from biopsy specimens of oral lesions in all patients with erosive OLP and presence of H. pylori in the stomach (9 patients), but in none of the patients with non-erosive OLP (P = 0.001).

CONCLUSION

We did not find any difference in symptoms, endoscopic findings and histopathological results between patients with erosive and non-erosive OLP. However, the concomitant presence of erosive OLP, of H. pylori nucleic acid in erosive OLP and the H. pylori organisms in gastric mucosa implies a possible pathogenic connection between this bacterium and erosive OLP.

Inhalation of Staphylococcus aureus enterotoxin A induces IFN-gamma and CD8 T cell-dependent airway and interstitial lung pathology in mice

Staphylococcus aureus, a primary source of bacterial superantigen (SAg), is known to colonize the human respiratory tract and has been implicated in airway inflammation. Studies have documented a role for SAgs in respiratory disorders, such as nasal polyps, chronic obstructive pulmonary disease, chronic rhinosinusitis, and asthma. However, cellular and molecular mediators involved in SAg-mediated pulmonary disease have not been clearly identified. In this study, we investigated the effect of intranasal staphylococcal enterotoxin A (SEA) exposure on murine lung. The pathological features in the lung resulting from SEA exposure had characteristics of both obstructive and restrictive pulmonary disorders. There was also an increase in bronchoalveolar lavage protein concentration and cellularity following SEA challenge. Massive CD8(+)Vbeta3(+) T cell accumulation observed in the lung was dependent on CD4 T cell help, both for recruitment and for IFN-gamma synthesis. The primary source of IFN-gamma synthesis was CD8 T cells, and depletion of these cells abrogated disease. IFN-gamma deficiency also prevented SEA-mediated disease, and this was by enhancing early recruitment of neutrophils as detected in the bronchoalveolar lavage. Thus, IFN-gamma appeared to selectively aid the recruitment of T cells to the lungs while preventing the neutrophil accumulation. Therefore, our results show that IFN-gamma-producing CD8 T cells mediated pulmonary alveolitis and inflammation, which were dependent upon CD4 T cells for their recruitment to the lung.

Regulation of Epidermal Tight-Junctions (TJ) during Infection with Exfoliative Toxin-Negative Staphylococcus Strains

Tight Junction (TJ) proteins have been shown to exert a barrier function within the skin. Here, we study the fate of TJ proteins during the challenge of the skin by bacterial colonization and infection. We investigated the influence of various exfoliative toxin-negative Staphylococcus strains on TJ, adherens junction (AJ), desmosomal proteins, and actin in a human keratinocyte infection culture and in a porcine skin infection model. We found that the pathogen Staphylococcus aureus downregulates TJ and subsequently AJ and desmosomal proteins, including atypical protein kinase C, an essential player in TJ formation, at the cell-cell borders of keratinocytes in a time and concentration dependent manner. Little changes in protein and RNA levels were seen, indicating redistribution of proteins. In cultured keratinocytes, a reduction of transepithelial resistance was observed. Staphylococcus epidermidis shows only minor effects. All strains induced enhanced expression of occludin and ZO-1 at the beginning of colonization/infection. Thus, we demonstrate that TJ are likely to be involved in skin infection of exfoliative toxin-negative S. aureus. As we did not find a change in actin, and as changes of TJ preceded alterations of AJs and desmosomes, we suggest that S. aureus targets TJ.

Role of bacterial pathogens in atopic dermatitis

The skin of atopic dermatitis (AD) patients exhibits a striking susceptibility to colonization and infection with Staphylococcus aureus. This review summarizes our understanding about the role of S. aureus in AD. Indeed, S. aureus colonization is both a cause and a consequence of allergic skin inflammation. The mechanisms that allergic skin inflammation of AD promotes the increase of S. aureus colonization include skin barrier dysfunction, increased synthesis of the extracellular matrix adhesins for S. aureus, and defective innate immune responses due to decreased production of endogenous antimicrobial peptides. On the other hand, the exotoxins secreted by S. aureus are superantigens. Staphylococcal superantigens (SsAgs) may penetrate the skin barrier and contribute to the persistence and exacerbation of allergic skin inflammation in AD through the stimulation of massive T cells, the role of allergens, direct stimulation of antigen-presenting cells and keratinocytes, the expansion of skin-homing cutaneous lymphocyte-associated antigen-positive T cells, and the augmentation of allergen-induced skin inflammation. SsAgs also induce corticosteroid resistance. In therapeutic interventions, anti-inflammatory therapy alone is very effective in reducing S. aureus colonization on the skin, but antibiotic treatment alone is unable to improve the allergic skin inflammation of AD. Therefore, we recommend the combination therapy of anti-inflammatory drugs and antibiotics in the AD patients with secondary bacterial infection, exacerbated AD, or poorly controlled AD. However, when AD is well controlled by anti-inflammatory drugs alone, we do not recommend the antibiotic therapy.

Innate immunity and antimicrobial defense systems in psoriasis

Psoriasis is a chronic inflammatory disorder that is mediated by elements of the innate and adaptive immune systems. Its characteristic features in the skin consist of inflammatory changes in both dermis and epidermis, with abnormal keratinocyte differentiation and proliferation. Despite the elucidation of many aspects of psoriasis pathogenesis, some puzzling questions remain to be answered. A major question currently debated is whether psoriasis is a primary abnormality of the epidermal keratinocyte or a reflection of dysregulated bone marrow-derived immunocytes. In this review we will focus on understanding the role of the innate immune system in psoriasis and how this provides a rational solution to address the origin of this multifactorial disease. Innate immunity is nonspecific and genetically based. It protects the body against the constant risk of pathogens through the use of rapidly mobilized defenses that are able to recognize and kill a variety of threats (bacteria, fungi, viruses, etc). The key mechanisms of innate immune responses are the existence of receptors to recognize pathogens and the production of factors that kill pathogens, such as antimicrobial peptides and proteins. Any combination of excessive sensitivity of the innate detection system, or dysregulation of the response system, can manifest both an epidermal phenotype and an abnormal T-cell function. Thus, the multidimensional action of the innate immune system, its triggers, and its recently understood role in T-cell function argue for an important role for innate mechanisms of recognition and response in the pathogenesis of psoriasis.

Bacterial superantigens and T cell receptor beta-chain-bearing T cells in the immunopathogenesis of ulcerative colitis

Ulcerative colitis (UC) is a chronic relapsing-remitting inflammatory bowel disease (IBD) that affects the colon and the rectum producing debilitating symptoms, which impair ability to function and quality of life. The aetiology of IBD is incompletely understood, but within the lymphocyte population, specific T cell subsets are known to be major factors in the development of intestinal immune pathology while different subsets are essential regulators, controlling IBD. Hence, IBD is thought to reflect dysregulated T cell behaviour. This study was to investigate if the normal molecular configuration of the T cell receptor (TCR) repertoire is compromised in patients with UC. The percentage of T cell-bearing beta-chain 4 (TCRBV4) was high in patients with UC, and T cells showed polyclonal expansion in the presence of bacterial superantigens (SA) such as streptococcal mitogenic exotoxin Z-2 (SMEZ-2), indicating that bacterial SA promote specific TCRBV family expansion. Further, in patients with UC, the duration of UC was significantly longer in patients with skewed TCRBV4 compared with patients without TCRBV4 skewing, suggesting that long-term exposure to bacterial SA such as SMEZ-2 might promote systemic immune disorders like the remission-relapsing cycles seen in patients with UC. In conclusion, our observations in this study support the perception that the systemic activation of T cells by enteric bacterial SA might lead to a dysregulated, but exuberant immune activity causing the remission and flare-up cycle of mucosal inflammation in patients with UC. Future studies should strengthen our findings and increase understanding on the aetiology of IBD.

Childhood pustular psoriasis associated with Panton-Valentine leukocidin-producing Staphylococcus aureus

We report the association of a generalized pustular psoriasis and infection by Staphylococcus aureus which produced Panton-Valentine leukocidin in a 5-year-old child. Another S. aureus strain with the same toxin gene content was also isolated among three family members presenting with cutaneous lesions. Although a methicillin-resistant staphylococcal strain has been reported in association with pustular psoriasis, this is the first report of a Panton-Valentine leukocidin strain associated with generalized pustular psoriasis. The causal relationship between S. aureus produced Panton-Valentine leukocidin and skin lesions is discussed.

The Role of Immune Response to Staphylococcus aureus Superantigens and Disease Severity in Relation to the Sensitivity to Tacrolimus in Atopic Dermatitis

BACKGROUND

Staphylococcus aureus-producing superantigens (SAgs), such as staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin-1 (TSST-1), are frequently observed in atopic dermatitis (AD). However, little has been done to establish the association of immune responses to SAgs and the therapeutic response to immunosuppressive drugs in AD. Therefore, we investigated the prevalence and role of SAgs in the pathophysiology and immunosuppressive drug sensitivity in AD patients.

METHODS

We classified 29 patients into two groups on the basis of their clinical AD scores: a low-score group (n = 14) corresponding to mild to moderate patients and a high-score group (n = 15) corresponding to severe patients. We estimated the plasma anti-SEB or TSST-1 IgE of these patients and healthy subjects by ELISA. We also estimated individual drug sensitivity by determining drug concentrations that would give 50% inhibition (IC(50)) of peripheral-blood mononuclear cell (PBMC) proliferation in vitro.

RESULTS

The levels of plasma anti-SEB or TSST-1 IgE in the severe patients were significantly higher than those in the mild to moderate patients (p < 0.05 and p < 0.01, respectively). When stimulated with concanavalin A in vitro, PBMCs in the severe patients exhibited low sensitivity to the suppressive efficacy of tacrolimus (FK506) as compared to the mild to moderate patients (p < 0.01). Furthermore, there was a significant correlation between the IC(50)s of FK506 and plasma anti-TSST-1 IgE levels (p < 0.01).

CONCLUSIONS

We showed that PBMCs in severe AD patients exhibited lower sensitivity to FK506, and had higher plasma levels of anti-TSST-1 IgE as compared to the mild AD patients. SAgs appear to be one of the causes of decreased PBMC sensitivity to FK506, and therefore an alternative treatment would be useful based on the individual drug sensitivity data and anti-TSST-1 IgE levels.

Peptidoglycan: a major aetiological factor for psoriasis?

Peptidoglycan (PG), a major cell-wall component of Gram-positive bacteria, has been detected within antigen-presenting cells in various inflammatory conditions, including psoriasis. The additional presence of T-helper 1 cells specific for streptococcal or staphylococcal PG in psoriasis skin lesions implicates PG as an important T-cell stimulator for the disease. PG is a major target for the innate immune system, and associations between genetic polymorphisms of recognition receptors for PG and various auto-inflammatory diseases have been identified. The location of these genes within four linkage sites for psoriasis raises the possibility that an altered innate recognition of PG might contribute to the enhanced T-cell response to the bacterial antigen. These observations suggest that PG is a major aetiological factor for psoriasis and emphasize the importance of PG in bacterial-infection-induced inflammatory disease.

Role of staphylococcal superantigen in atopic dermatitis: influence on keratinocytes

Staphylococcus aureus may perform an crucial function in atopic dermatitis (AD), via the secretion of superantigens, including staphylococcal enterotoxins (SE) A or B, and toxic shock syndrome toxin-1 (TSST-1). Dysregulated cytokine production by keratinocytes (KCs) upon exposure to staphylococcal superantigens (SsAgs) may be principally involved in the pathophysiology of AD. We hypothesized that lesional KCs from AD may react differently to SsAgs compared to nonlesional skin or normal skin from nonatopics. We conducted a comparison of HLA-DR or CD1a expression in lesional skin as opposed to that in nonlesional or normal skin by immunohistochemistry (IHC). We also compared, using ELISA, the levels of IL-1alpha, IL-1beta, and TNF-alpha secreted by cultured KCs from lesional, nonlesional, and normal skin, after the addition of SEA, SEB and TSST-1. IHC revealed that both HLA-DR and CD1a expression increased significantly in the epidermis of lesional skin versus nonlesional or normal skin in quite a similar manner. IL-1alpha, IL-1beta, and TNF-alpha secretion was also significantly elevated in the cultured KCs from lesional skin after the addition of SsAgs. Our results indicated that KCs from lesional skin appear to react differently to SsAgs and increased proinflammatory cytokine production in response to SsAgs may contribute to the pathogenesis of AD.

Glycerol monolaurate inhibits the effects of Gram-positive select agents on eukaryotic cells

Many exotoxins of Gram-positive bacteria, such as superantigens [staphylococcal enterotoxins, toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxins] and anthrax toxin are bioterrorism agents that cause diseases by immunostimulation or cytotoxicity. Glycerol monolaurate (GML), a fatty acid monoester found naturally in humans, has been reported to prevent synthesis of Gram-positive bacterial exotoxins. This study explored the ability of GML to inhibit the effects of exotoxins on mammalian cells and prevent rabbit lethality from TSS. GML (>or=10 microg/mL) inhibited superantigen (5 microg/mL) immunoproliferation, as determined by inhibition of (3)H-thymidine incorporation into DNA of human peripheral blood mononuclear cells (1 x 10(6) cells/mL) as well as phospholipase Cgamma1, suggesting inhibition of signal transduction. The compound (20 microg/mL) prevented superantigen (100 microg/mL) induced cytokine secretion by human vaginal epithelial cells (HVECs) as measured by ELISA. GML (250 microg) inhibited rabbit lethality as a result of TSST-1 administered vaginally. GML (10 microg/mL) inhibited HVEC and macrophage cytotoxicity by anthrax toxin, prevented erythrocyte lysis by purified hemolysins (staphylococcal alpha and beta) and culture fluids containing streptococcal and Bacillus anthracis hemolysins, and was nontoxic to mammalian cells (up to 100 microg/mL) and rabbits (250 microg). GML stabilized mammalian cell membranes, because erythrocyte lysis was reduced in the presence of hypotonic aqueous solutions (0-0.05 M saline) or staphylococcal alpha- and beta-hemolysins when erythrocytes were pretreated with GML. GML may be useful in the management of Gram-positive exotoxin illnesses; its action appears to be membrane stabilization with inhibition of signal transduction.

A new endogenous retroviral sequence is expressed in skin of patients with psoriasis

BACKGROUND

The origin of psoriasis, a chronic inflammatory skin disease involving keratinocyte proliferation, immune disturbances and complex inheritance, remains unknown. Human endogenous retroviruses (HERVs) are part of the normal human genome and their participation in the pathogenesis of various human diseases with complex genetic traits has been proposed. A possible role of HERVs in the induction of psoriasis was suggested many years ago. However, to date no study has searched for HERV expression in psoriasis.

OBJECTIVES

To determine firstly, which HERV families are expressed in the psoriatic lesion and secondly, whether specific variants can be detected.

METHODS

HERV expression was analysed at the mRNA level after degenerated reverse transcription-polymerase chain reaction (RT-PCR) of retroviral pol sequences followed by sequencing. Screening for a specific variant was performed by RT-PCR on lesional and nonlesional psoriatic skin and compared with normal and atopic dermatitis skin.

RESULTS

We report the expression of three HERV families in psoriatic lesions, namely HERV-W, K and E. We then partially characterized a new endogenous retroviral variant, which was related to the ERV-9/HERV-W family. This sequence contains at least two open reading frames that could encode for a gag protein and a retroviral protease. The expression of this sequence was detected in 29 of 43 lesional psoriasis skin samples and rarely in normal (two of 21) or atopic dermatitis (three of 14) skin samples.

CONCLUSIONS

In psoriatic lesions, HERV sequences of the W, K and E families are expressed and a new variant of the ERV-9/HERV-W family has been characterized. The possible role of HERV-related sequences in the pathogenesis of psoriasis is under investigation.

Bactericidal activity of flucloxacillin against Staphylococcus aureus in primary keratinocyte cultures of lesional and unaffected skin of patients suffering from atopic dermatitis

More than 90% of patients with atopic dermatitis (AD) are colonized by Staphylococcus aureus. Due to prevalent multi-resistant strains, it is highly difficult to eliminate S. aureus contamination of primary cell cultures of human AD skin by means of the antibiotics commonly used in cell culture. Therefore, an anti-staphylococcal treatment was investigated by which sterile proliferating keratinocyte cultures are attained from lesional and unaffected skin of AD patients by applying flucloxacillin, which in general is systemically used in vivo. The treatment with 1% flucloxacillin for 20 min included both colonized skin samples and contaminated primary cell cultures. In the case of persistent contamination, this step was repeated as often as required until complete decontamination without any cytotoxic indications was achieved. Antibacterial treatment with flucloxacillin permitted the cultivation of sterile, vital, and proliferating primary cultures of human skin keratinocytes from lesional and unaffected skin of AD patients with S. aureus colonization. The method increased the success rate of isolation of AD keratinocytes from 30 to 90%, representing on average 3 vs. 9 successfully isolated, sterile and proliferating cultures out of 10 contaminated skin biopsies, which is comparable to normal human keratinocyte isolation rates.

Role of human mast cells and basophils in bronchial asthma

Mast cells and basophils are the only cells expressing the tetrameric (alphabetagamma2) structure of the high affinity receptor for IgE (FcepsilonRI) and synthesizing histamine in humans. Human FcepsilonRI+ cells are conventionally considered primary effector cells of bronchial asthma. There is now compelling evidence that these cells differ immunologically, biochemically, and pharmacologically, which suggests that they might play distinct roles in the appearance and fluctuation of the asthma phenotype. Recent data have revealed the complexity of the involvement of human mast cells and basophils in asthma and have shed light on the control of recruitment and activation of these cells in different lung compartments. Preliminary evidence suggests that these cells might not always be detrimental in asthma but, under some circumstances, they might exert a protective effect by modulating certain aspects of innate and acquired immunity and allergic inflammation.

Suprabasal expression of human amphiregulin in the epidermis of transgenic mice induces a severe, early-onset, psoriasis-like skin pathology: expression of amphiregulin in the basal epidermis is also associated with synovitis

The expression of amphiregulin (AR) in the basal epidermis of transgenic mice [keratin 14 promoter AR gene (K14-ARGE)] has been previously shown to induce an early-onset and severe skin pathology, with many similarities to psoriasis. In this study, it is demonstrated that involucrin enhancer/promoter-dependent expression of human AR (INV-AR) in the suprabasal epidermis of transgenic mice also produces a cutaneous psoriasis-like phenotype. INV-AR mice possess a limited lifespan and scaling, papillomatous, erythematous skin with partial alopecia. INV-AR mouse histopathology also revealed epidermal hyperkeratosis, parakeratosis, acanthosis, and an exaggerated dermal vasculature. A dermal and epidermal infiltrate was also evident and consisted of both neutrophils and CD3(+) T lymphocytes. The histology of synovial joints in both the INV-AR mice and the K14-ARGE mice of our previous investigation was examined. The histologic examination revealed that 3-week-old INV-AR transgenic mice displayed normal knee joint histology, while 2- to 3-week-old K14-ARGE transgenic mice frequently displayed synovitis, as exemplified by the presence of a mixed leukocytic infiltration, increased vascularization, and enhanced deposition of fibrous matrix in the knee synovium. These results demonstrate that AR overexpression in both the basal and suprabasal epidermis of transgenic mice induces a phenotype that mimics cutaneous psoriasis, while basal AR expression is also associated with synovial inflammation, a precursor to the psoriasis-associated arthropathy, psoriatic arthritis. Collectively, the results implicate epidermal AR expression as a possible mediator of innate cutaneous immunity and epidermal proliferation and also as a potential trigger of both cutaneous psoriasis and psoriatic arthritis.

Immunoglobulin E- (IgE) and non-IgE-mediated reactions in the pathogenesis of atopic eczema/dermatitis syndrome (AEDS)

AEDS is a chronic, relapsing, highly pruritic inflammatory skin disease that commonly begins in childhood. Two forms of this disorder exist, i.e. an allergic (extrinsic) form and a nonallergic (intrinsic) form. There are clear genetic, humoral and cellular differences between the allergic and nonallergic forms of AEDS. The allergic variants express local IgE production in affected tissue and both allergic and nonallergic triggers play a major role in the expression of disease. The role of allergens is very important in the immunopathogenesis of AEDS. Nonimmunological triggers play a secondary modulatory role often hampering treatment effort and optimal response to therapeutic efforts.

Severe Radiation Dermatitis is Related to Staphylococcus Aureus

Acute radiation dermatitis commonly occurs following local radiation therapy for various cancers and, when severe, may necessitate disruption of treatment. Intense inflammatory reaction may result in a breakdown of the skin's barrier function and accompanying bacterial colonization. Bacterial superantigens may exacerbate inflammation through activation of T-cells and subsequent cytokine release. We report six cases of severe radiation dermatitis in cancer patients. Four of the six grew pathogenic bacteria, and three had psoriasiform or eczematous reactions at distant sites. Both the radiation dermatitis and the distant cutaneous reactions resolved rapidly on a combination of topical steroids and oral plus topical antibiotic therapy. We suggest that staphylococcal superinfection of acute radiodermatitis intensifies the inflammatory process and hinders repair of the epidermal barrier. Patients with acute radiation dermatitis should be investigated for secondary infection. We emphasize the importance of including topical and oral antibiotic therapy in conjunction with topical corticosteroids to eradicate infection as well as hasten repair of the skin's barrier function. These cases are presented to call attention to the role of Staphylococcus aureus in the pathogenesis of severe radiation dermatitis and the need to include appropriate antibiotic therapy based on culture in the management of acute radiation dermatitis.

Immunomodulation and immunodeficiency

This article briefly reviews the concepts of immunodeficiency and immunomodulation as they relate to selected skin diseases in the dog and cat. Immunodeficiency states are uncommon and may be associated with a subnormal or down-regulated immune system, including humoral deficiencies, such as IgA, and abnormal lymphocyte or neutrophil function. Establishing a causal relationship between a skin disease and presumed immunodeficient state has been difficult due to the rarity of such conditions, and the limited nature of the techniques used to characterise the immune system response. Severe combined immunodeficiency in dogs is a well characterised primary immunodeficiency state involving lymphocytes; retrovirus infection in cats may lead to an acquired immunodeficient state with some association with certain dermatological conditions although it remains unclear that infection is causally linked with disease. Immunomodulation usually implies stimulating the immune system along a beneficial pathway. Such a therapeutic approach may involve a wide variety of agents, for example intravenous immunoglobulin. There are few randomised controlled trials with veterinary patients that unequivocally demonstrate beneficial responses to immunomodulatory agents. Interferons are cytokines of major interest in human and veterinary medicine for their antiviral, anti-tumour and immunomodulatory effects. The advent of veterinary-licensed products containing recombinant interferon may enable demonstration of the efficacy of interferons for conditions such as canine papillomatosis and feline eosinophilic granuloma complex. Canine pyoderma has been treated with a number of presumed immunomodulatory agents with limited success. With more detailed knowledge of the pathogenesis of pyoderma it may be possible to develop efficacious immunomodulators.

High frequency of detection of human papillomaviruses associated with epidermodysplasia verruciformis in children with psoriasis

BACKGROUND

Psoriasis is a T-cell-mediated immunological disease characterized by epidermal proliferation. The nature of the antigen(s) responsible for T-cell activation is still unknown. It has been suggested that the human papillomaviruses (HPVs) associated with epidermodysplasia verruciformis (EV), including the oncogenic HPV5, may contribute to the pathogenesis of psoriasis.

OBJECTIVES

To determine whether EV-HPVs may play a role early in the disease, we searched for these viruses in children with psoriasis. The influence of clinical data on EV-HPV infection was investigated.

METHODS

We studied scrapings of involved skin from 26 children aged 1.5-13 years with psoriasis. As controls, we analysed scrapings from 28 adults with psoriasis and 15 children with atopic dermatitis, as well as scrapings from normal skin of 28 adults with no known history of HPV infection. We searched for EV-HPV DNA sequences with a nested polymerase chain reaction method using degenerate primers specific for EV-HPVs and primers specific for HPV5 and HPV36, two EV-HPVs frequently detected in adults with psoriasis.

RESULTS

Similar high prevalences were observed in children and adults with psoriasis for EV-HPVs (38.5% vs. 35.7%), HPV5 (46.2% vs. 46.4%) and HPV36 (15.4% vs. 25.0%). As in adults, we found several EV-HPV genotypes and HPV5 and HPV36 variants. A novel HPV36 subtype, HPV36b, was identified. Lower prevalences were observed in children with atopic dermatitis and in adults from the general population (6.7-10.1%). No correlation was observed between frequency of detection of HPVs and clinical data. It is noteworthy that HPV5 was identified in an 18-month-old girl and in a boy with psoriasis developing for only 1 week.

CONCLUSIONS

The early detection of several EV-HPV genotypes in children further supports the link between psoriasis and EV-HPVs and suggests a putative role for these viruses in the pathogenesis of psoriasis.

High levels of fusidic acid-resistant Staphylococcus aureus in dermatology patients

BACKGROUND

Antibiotic resistance is a significant problem both in hospitals and the community. Topical antibiotics are widely used for dermatological problems and this may be leading to the emergence of resistant bacteria.

OBJECTIVE

To assess the level of fusidic acid-resistant Staphylococcus aureus inpatients with dermatological problems.

METHODS

All microbiology samples over a 4-month period were tested for antibiotic sensitivities. Patients with cultures positive for S. aureus were studied.

RESULTS

The study shows 50% of S. aureus isolates from dermatology patients were resistant to fusidic acid. This figure rose to 78% inpatients with atopic eczema. Of patients with fusidic acid-resistant S. aureus isolates, 96% had used a fusidic acid-containing preparation within the previous 6 months. The level of fusidic acid resistance in S. aureus samples cultured from nondermatology patients was only 9.6%, a level significantly below that for dermatology patients (P < 0.001).

CONCLUSIONS

High levels of fusidic acid-resistant S. aureus are found in dermatology patients. Inappropriate use of topical antibiotics in dermatology patients leading to fusidic acid resistance may threaten the efficacy of systemic fusidic acid for the treatment of serious S. aureus infections. Education of health professionals and restriction of the use of fusidic acid is needed.

Augmentation of staphylococcal alpha-toxin signaling by the epidermal platelet-activating factor receptor

Staphylococcal alpha-toxin is a cytolytic toxin secreted by many strains of Staphylococcus aureus that has proinflammatory and cytotoxic effects on human keratinocytes. alpha-toxin exerts its effects by forming a transmembrane pore that behaves like an ionophore for ions such as calcium. Because cellular membrane disruption with resultant intracellular calcium mobilization is a potent stimulus for the synthesis for the lipid mediator platelet-activating factor, the ability of alpha-toxin to induce platelet-activating factor production was assessed, and whether the epidermal platelet-activating factor receptor could augment toxin-induced signaling in epithelial cells examined. Treatment of the human keratinocyte-derived cell line HaCaT with alpha-toxin resulted in significant levels of platelet-activating factor, which were approximately 50% of the levels induced by calcium ionophore A23187. alpha-toxin also stimulated arachidonic acid release in HaCaT keratinocytes. Pretreatment of HaCaT cells with platelet-activating factor receptor antagonists, or overexpression of the platelet-activating factor metabolizing enzyme acetylhydrolase II blunted alpha-toxin-induced arachidonic acid release by approximately one-third, suggesting a role for toxin-produced platelet-activating factor in this process. Finally, retroviral-mediated expression of the platelet-activating factor receptor into the platelet-activating factor receptor-negative epithelial cell line KB resulted in an augmentation of alpha-toxin-mediated intracellular calcium mobilization and arachidonic acid release. These studies suggest that alpha-toxin-mediated signaling can be augmented via the epidermal platelet-activating factor receptor.

Subclinical activation of latent cytomegalovirus (CMV) infection and anti-CMV immune response in patients with atopic dermatitis

BACKGROUND

Microbiological infections are considered to be of pathophysiological importance in atopic dermatitis (AD). As yet, no information is available regarding cytomegalovirus (CMV) infection in this disease. This, however, is of interest because of the high prevalence of latent infections in the general population, the frequent reactivation in inflammatory diseases, and the immunomodulating capacity of CMV.

OBJECTIVES

To investigate the prevalence of latent CMV infection, the frequency of active CMV infection, and the immune response to CMV in patients with moderate to severe AD. Methods To detect active infection we analysed CMV antigen expression by peripheral blood mononuclear cells (PBMC) from 27 patients with moderate to severe AD in comparison with 53 healthy volunteers. We used three monoclonal antibodies recognizing different CMV-encoded antigens and immunocytological staining (alkaline phosphatase-antialkaline phosphatase technique).

RESULTS

Patients with AD had a higher mean frequency of CMV-positive PBMC: 2.25 per 10 000 vs. 0.74 per 10 000 in controls (P = 0.001) as well as a higher incidence of CMV antigenaemia: 29.6% vs. 7.5% (P < 0.01). Seropositivity for anti-CMV IgG antibodies indicated subclinical activation of latent infection. Remarkably, a clearance of CMV antigenaemia was observed during anti-eczematous treatment. Significantly higher plasma levels of tumour necrosis factor-alpha, which is involved in CMV reactivation, and interleukin-12, which is crucial for an antiviral cellular immune response, were observed in AD patients in comparison with healthy volunteers. Furthermore, a significantly enhanced frequency of circulating activated HLA-DR+ T cells especially in CMV-seropositive AD patients (19.3% vs. 13.5% in seronegative AD patients vs. 10.2% in controls) suggested that the active CMV infection triggers a cellular immune response. This was also supported by a high frequency of CMV-specific interferon-gamma-producing T cells in CMV-seropositive patients with AD.

CONCLUSIONS

Our data suggest that active, subclinical CMV infection is more frequent in patients with moderate to severe AD and may have immunopathophysiological relevance.

Treatment of psoriasis in children: is there a role for antibiotic therapy and tonsillectomy?

Numerous studies implicate subclinical or recurrent streptococcal infection as a trigger or maintenance factor in the pathogenesis of psoriasis in children. The purpose of this article is to review the efficacy of antibiotic therapy and tonsillectomy as treatments for childhood psoriasis. Clinical trials assessing the efficacy of antibiotics or tonsillectomy as treatments for childhood psoriasis were identified with a search of the medical literature and the results were compared. Only one controlled clinical trial was identified and it did not find a significant effect of antibiotic treatment on psoriasis. In other studies, the percentage of psoriasis patients who experienced disease clearance with antibiotic therapy ranged from 0% to 55%, with no patients experiencing disease worsening during treatment. No controlled trials of tonsillectomy for psoriasis were identified. The percentage of patients who experienced disease clearance after tonsillectomy in uncontrolled trials ranged from 32% to 53% and a similar percentage reported significant improvement in their psoriasis, with a maximum of 7% noting worsening of the disease after the operation. The available evidence does not demonstrate the efficacy of either antibiotic therapy or tonsillectomy in the treatment of childhood psoriasis. Because these treatments are relatively benign compared to other treatments for severe psoriasis, the use of antibiotic therapy or tonsillectomy may still be worth considering, especially for those patients with recurrent streptococcal infections that seem to trigger or maintain their skin disease.

Frequency of superantigen-producing Staphylococcus intermedius isolates from canine pyoderma and proliferation-inducing potential of superantigens in dogs

This preliminary study investigated the potential role of staphylococcal superantigens in the pathogenesis of canine pyoderma. The staphylococcal enterotoxins A (SEA), SEB, SEC and SED, and the toxic shock syndrome toxin-1 (TSST-1) were assayed in isolates from skins of dogs with pyoderma. Culture supernatants from 25 of 96 isolates were positive for multiple superantigens, with SEA and SEC being the most frequently detected. In in vitro stimulation of canine peripheral blood mononuclear cells and quantitative flow cytometry revealed that low concentrations of SEA and SEB were potent stimulators of blastogenesis of T cells.

Different mechanisms are utilized by HIV-1 Nef and staphylococcal enterotoxin A to control and regulate interleukin-10 production

Interleukin-10 (IL-10) plays an important immunopathogenic role in immunologic diseases, especially in HIV infection and atopic dermatitis. The control and regulatory mechanisms of IL-10 production have not been described in these diseases. Recently, we demonstrated that HIV-1 Nef induces IL-10 production in monocytes and that staphylococcal enterotoxin A (SEA) induces IL-10 production in T-lymphocytes. Here we show that Nef-induced IL-10 production and mRNA expression are strongly blocked by rapamycin, but are not blocked by cyclosporin (CsA) or FK506. Conversely, we show that CsA and FK506 completely inhibit SEA-induced IL-10 protein production and mRNA expression. The results of this study demonstrate that IL-10 production by Nef and SEA is controlled and regulated by different mechanisms.

Atopic dermatitis and fungi

Atopic dermatitis (AD) is a chronic, itching, inflammatory skin disease which is associated with asthma and/or hay fever and a familial occurrence of these conditions. Genetic factors are important in the development of AD, but the exact hereditary pathway is still unknown. Dry skin and the weakened barrier function in patients with AD is very important for the patient's reactions to irritants and other external trigger factors including microorganisms. The standard treatments are topical corticosteroids, topical immunomodulating agents, and emollients. If AD cannot be controlled by this type of treatment, systemic immunomodulating agents may be used. UVB, UVA, or psoralen-UVA may also be used for widespread severe lesions. However, some patients do not respond to these standard treatment, and then it is important to consider the role of microorganisms, house dust mites or food. The role of the Malassezia yeasts in AD, especially AD located to the head and neck region, is now documented in several papers. There are also several papers indicating the role of Candida as an aggravating factor in AD. Patients with AD also develop chronic dermatophyte infections more easily, and patients with AD and chronic dermatophyte infections may show improvement in their AD when treated with antifungal drugs.

Helicobacter pylori infection in skin diseases: a critical appraisal

More than 50% of the human population have long-term Helicobacter pylori infection, causing, in some cases, severe diseases such as peptic ulcers and stomach cancer. In the last few years several extra-gastrointestinal disorders have been associated with H. pylori infection. This review summarized the current medical literature, identified through hand searching and MEDLINE research, including our own studies, with regard to H. pylori and skin diseases. From the literature it can be seen that the role of H. pylori in skin diseases is still a controversial subject. Randomized controlled trials with adequate masking and sample sizes are still lacking. The best evidence comes from studies investigating chronic urticaria in which chronic urticaria disappeared in many patients with H. pylori infection after careful eradication of the H. pylori. Moreover, there are promising recent reports of beneficial H. pylori eradication in Behçet's disease, pruritus cutaneus, prurigo chronica, prurigo nodularis and in some patients with lichen planus, but not in rosacea or psoriasis. Before any conclusions with respect to other skin diseases such as atopic dermatitis, Schoenlein-Henoch Purpura, Sweet's syndrome, Sjögren syndrome or systemic sclerosis may be drawn, additional randomized, double-blinded and placebo-controlled studies including adequate diagnostic schedules, sufficient eradication treatment protocols, confirmation of eradication and adequate control groups are needed. The cutaneous pathology of H. pylori is far from being clear, but it is speculated that the systemic effects may involve increased mucosal permeability to alimentary antigens, immunomodulation, an autoimmune mechanism or the impairment of vascular integrity.

Tacrolimus: a review of its use for the management of dermatoses

The newly developed immunomodulator tacrolimus (FK506) is the first of a new class of agents that have enormous potential to change the way that dermatoses are treated and managed. Tacrolimus has been found to be active in a topical formulation with the latter exerting its effects by acting on the signal transduction pathways inside T cells and inhibiting gene transcription. The result is decreased responsiveness of T cells to antigens. Percutaneous absorption of tacrolimus is higher in diseased skin as opposed to healthy skin and, therefore, the drug will be taken in at progressively lower quantities as lesions heal. There is limited systemic absorption of tacrolimus over the course of therapy. The most extensive experience with tacrolimus has been in treating atopic dermatitis. In numerous trials, tacrolimus ointment 0.03-0.3% has shown to be effective in reducing the symptoms and severity of atopic dermatitis in adults and the paediatric population. Furthermore, there have been no significant toxic effects associated with topical therapy with tacrolimus. The most common complaint is that of local irritation after applying the ointment. This is generally transient and the patient is able to continue with therapy. The other dermatoses where tacrolimus has been used include contact dermatitis, psoriasis and pyoderma gangrenosum.

The keratinocyte as a target for staphylococcal bacterial toxins

Skin infections with Staphylococcus aureus are not only an important cause of morbidity and even mortality, but are thought to serve as initiation and/or persistance factors for numerous inflammatory skin diseases, including psoriasis and atopic dermatitis. One mechanism by which S. aureus can modulate the immune system is through the production of proteins such as superantigenic toxins, Protein A, as well through the cytolytic alpha-toxin. This review serves to discuss the biology of these three types of proteins, with emphasis on their ability to stimulate the production of powerful pro-inflammatory lipid- and protein-derived cytokines in keratinocytes. Characterization of interactions between these proteins and the keratinocyte can provide a better understanding of how bacterial infection modulates inflammatory skin diseases, as well as provide the basis for improved therapies involving antibacterial agents.

Guttate psoriasis following Kawasaki disease

Guttate psoriasis developed in a 3.5-year-old boy during the course of Kawasaki disease (KD). The pathogenesis of this unusual complication may be production of superantigens, which is also considered to be a cause of KD.

Ontogeny of T-helper 1 and T-helper 2 cytokine production in childhood

Compared to adults, infants and young children demonstrate differences in their immune response, indicating that there is maturation or change over time and it is probable that this may be reflected in cytokine production. Cytokine responses have been demonstrated to be different in atopic and non-atopic individuals. In this study, we examined T-helper 1 (Th1) (interferon-gamma [IFN-gamma]) and T-helper 2 (Th2) (interleukin [IL]-4, IL-5, and IL-13) cytokine release from atopic and non-atopic children in response to the staphylococcal superantigen, staphylococcal enterotoxin B (SEB). In non-atopic and atopic children, IFN-gamma, IL-4, and IL-5 release was significantly related to age. Non-atopic children younger than 2 years of age were found to have significantly reduced Th2 (IL-4, IL-5, and IL-13) responses when compared with older, non-atopic children. Atopic children had a reduced IFN-gamma response when compared with non-atopics in early childhood; however, the decreased IFN-gamma response seen in early childhood did not persist after 10 years. These age-related changes in cytokine production provide further support for the concept that cytokine deviations may determine the natural history of atopic disease during early childhood. In addition, the present study indicates the necessity of age-matched controls when examining children for both Th1 (IFN-gamma) and Th2 (IL-4) cytokine release.

Patients with allergic and irritant contact dermatitis are characterized by striking change of iron and oxidized glutathione status in nonlesional area of the skin

To assess the consequences of oxidative stress in allergic and irritant contact dermatitis, we compared the iron level, unsaturated iron-binding capacity, total iron binding capacity, the percentage saturation of iron-binding capacity, the amount of diene conjugates as well as the amounts of total glutathione, reduced glutathione, oxidized glutathione, and the oxidized glutathione/reduced glutathione ratio in skin homogenate from lesional and nonlesional skin. Lesional skin samples were obtained from positive patch test sites to 5% NiSO4 in five subjects, and from chronic contact dermatitis lesions on the hands, which had exacerbated over 3--9 wk in six subjects. Contact dermatitis caused at least a 4-fold increase in the iron level in the lesional skin area compared with the nonlesional skin area (p < 0.02). The increase in the iron level depended on the duration of contact dermatitis and was accompanied by high unsaturated iron-binding capacity and total iron-binding capacity values in the positive patch test sites (p < 0.05), and by a high percentage saturation value in the chronic contact dermatitis lesions (p < 0.05). We found high indices for iron, total iron-binding capacity and diene conjugates in the apparently healthy skin of the patients with persistent contact dermatitis that significantly (p < 0.05) exceeded the corresponding values in the patients with only patch test reactions. In summary, we have succeeded in providing evidence that generalized oxidative damage of the skin occurs as a consequence of contact dermatitis in a restricted area.

Treatment of psoriatic arthritis with antitumour necrosis factor-alpha antibody clears skin lesions of psoriasis resistant to treatment with methotrexate

BACKGROUND

In inflamed skin, keratinocytes and inflammatory cells both produce large amounts of tumour necrosis factor (TNF) -alpha, a cytokine with broad effects that are relevant to inflammation. Blockade of this proinflammatory cytokine by a monoclonal anti-TNF-alpha antibody might be effectively used in the treatment of inflammatory skin diseases.

OBJECTIVES

To gather information about the efficacy of an anti-TNF-alpha antibody (infliximab) in the treatment of skin lesions of psoriatic arthritis.

METHODS

Six patients with progressive joint disease and psoriatic skin lesions unresponsive to methotrexate therapy were treated with anti-TNF-alpha antibody. The Psoriasis Area and Severity Index was determined before and 10 weeks after initiation of therapy.

RESULTS

Improvement of psoriatic skin lesions was observed in all patients. In addition, a marked improvement of the joint disease was noted.

CONCLUSIONS

Therapy with anti-TNF-alpha antibody may be an effective treatment regimen for both psoriatic arthritis and psoriatic skin lesions.

Atopic dermatitis: pathogenetic mechanisms

Atopic dermatitis (AD) is a chronic inflammatory skin disease with increasing incidence and socio-economical relevance. The diagnosis is made on clinical grounds and different diagnostic criteria sets have been established. The majority of all AD cases is associated with a sensitization to environmental allergens and increased serum IgE (so-called extrinsic AD), but about 10--30% of all cases suffer from the so-called intrinsic AD, which obviously lacks any link to the classical atopic diathesis. The genetic background of AD has been investigated by target gene approach by different groups with mostly contradictory results for each of the genes under study. An imbalance in the spectrum of Th1/Th2 responses, a disturbed prostaglandin metabolism, intrinsic defects in keratinocyte function, delayed eosinophil apoptosis, IgE-mediated facilitated antigen presentation by epidermal dendritic cells, a two phase model of the inflammatory response and staphylococcal superantigen effects are among the currently studied pathogenetical aspects of extrinsic AD, which are reviewed in this paper.

Treatment of patients hospitalized for psoriasis

Life quality of patients with severe forms of psoriasis can be greatly improved with an appropriate inpatient therapy. In an effort to better understand how to treat this disorder, this article explores several aspects of inpatient treatment for severe psoriasis. Special attention is given to the Goeckerman regimen, combination therapies, and some innovative approaches that may shorten the hospital stay and prolong the remission periods of the disease.

Colonization with superantigen-producing Staphylococcus aureus is associated with increased severity of atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with colonization of the skin with Staphylococcus aureus known to produce toxins with superantigen (SAg) activity. Besides T-cell activation these toxins induce T-cell skin homing in vitro. This may contribute to the observed induction or enhancement of skin inflammation.

OBJECTIVE

The aim of this study was to determine whether colonization with SAg-producing S. aureus isolates modulates the intensity of AD. If so, it was of interest whether this may be primarily due to the toxins' effects as SAgs or as allergens.

METHODS

In AD patients, healthy controls, and atopic controls SAg production by S. aureus isolated from skin or mucous membranes was investigated and correlated to the severity of the disease. Total IgE, SAg-specific IgE, and T-cell activation and recirculation markers were analysed and correlated with SAg production.

RESULTS

Fifty-seven percent of S. aureus strains isolated from AD patients produced SAgs. This frequency was higher compared to healthy controls (33%). SAg production by S. aureus was correlated with a significantly higher scoring of AD (SCORAD index, 58 +/- 19 in SAg-producing vs 41 +/- 7 in non-SAg-producing germs; P < 0.05). However, the severity of the disease was not associated with sensitization against the SAgs staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin B (SEB). Furthermore, SAg production by S. aureus was inversely correlated with total IgE concentration (P < 0.05) and positively correlated with T-cell activation (as measured by HLA-DR and CD69 expression) and the expression of the T-cell skin homing phenotype cutaneous lymphocyte-associated antigen.

CONCLUSION

SAg production by S. aureus is suggested to be associated with an increased severity of atopic dermatitis. Since SAg production was found neither exclusively in AD patients nor in all patients, other pathogenic factors may be additionally effective.