PEP-1-PON1 protein regulates inflammatory response in raw 264.7 macrophages and ameliorates inflammation in a TPA-induced animal model

Paraoxonase 1 (PON1) is an antioxidant enzyme which plays a central role in various diseases. However, the mechanism and function of PON1 protein in inflammation are poorly understood. Since PON1 protein alone cannot be delivered into cells, we generated a cell permeable PEP-1-PON1 protein using protein transduction domains, and examined whether it can protect against cell death in lipopolysaccharide (LPS) or hydrogen peroxide (H₂O₂)-treated Raw 264.7 cells as well as mice with 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced skin inflammation. We demonstrated that PEP-1-PON1 protein transduced into Raw 264.7 cells and markedly protected against LPS or H₂O₂-induced cell death by inhibiting cellular reactive oxygen species (ROS) levels, the inflammatory mediator’s expression, activation of mitogen-activated protein kinases (MAPKs) and cellular apoptosis. Furthermore, topically applied PEP-1-PON1 protein ameliorates TPA-treated mice skin inflammation via a reduction of inflammatory response. Our results indicate that PEP-1-PON1 protein plays a key role in inflammation and oxidative stress in vitro and in vivo. Therefore, we suggest that PEP-1-PON1 protein may provide a potential protein therapy against oxidative stress and inflammation.

[Effect of deltaran and melatonin on immune system in rats with experimental contact dermatitis]

The aim of the work was investigation of both humoral and cell-mediated immunity together with leukocytes functional stability indexes in rats with the experimental contact dermatitis (ECD) in conditions of complex pharmacological correction using deltaran and melatonin. Experimental trials were performed under conditions of chronic experiment on model chrome-induced ECD. Both deltaran and melatonin either alone or in combination were used for complex pharmacological correction of humoral and cell-mediated immunity and also for stability of leukocytes. The data obtained showed the expressed disturbances of humoral and cell-mediated immunity and neutrophils' functional stability damage under conditions of chrome-induced ECD in rats. The revealed alterations in functional activity of the immune system were successfully corrected using the combined administration of deltaran and melatonin. The activity of medical complex had exponential character.

The role of IL-22 and Th22 cells in human skin diseases

Interleukin (IL)-22 is a cytokine that is involved in the modulation of tissue responses during inflammation. It is produced by immune cell subsets such as T cells, while the expression of its receptor is restricted to cells of non-hematopoietic origin, particularly epithelial cells. In the skin, IL-22 induces keratinocyte proliferation and epidermal hyperplasia, inhibits terminal differentiation of keratinocytes, and promotes the production of antimicrobial proteins. Although IL-22 was initially thought to be produced by T helper (Th)17 cells, IL-22 production can also occur in an apparently unique subset of cells, Th22 cells, which lack the ability to produce IL-17 and interferon-γ. Of note, Th22 cells, which express the skin homing chemokine receptors CCR4 and CCR10, reside in the normal skin and are enriched in the lesional skin of inflammatory skin diseases, indicating the importance of IL-22 in skin homeostasis and pathogenesis of skin diseases. Although a critical role of IL-22 was initially highlighted in psoriasis, a growing body of evidence indicates that this cytokine also plays a role in atopic dermatitis and other inflammatory skin diseases. Moreover, emerging experimental data suggest that IL-22 also participates in the pathophysiology of malignancies of the skin. In this review, recent findings regarding the expression, regulation, and function of the IL-22 pathway in various human skin diseases will be discussed. Considering the strong association between excess activation of the IL-22/Th22 pathway and human skin diseases, targeting this pathway may provide promising new therapeutic approaches.

A unique dermal dendritic cell subset that skews the immune response toward Th2

Dendritic cell (DC) subsets in the skin and draining lymph nodes (LNs) are likely to elicit distinct immune response types. In skin and skin-draining LNs, a dermal DC subset expressing macrophage galactose-type C-type lectin 2 (MGL2/CD301b) was found distinct from migratory Langerhans cells (LCs) or CD103⁺ dermal DCs (dDCs). Lower expression levels of Th1-promoting and/or cross-presentation-related molecules were suggested by the transcriptome analysis and verified by the quantitative real-time PCR analysis in MGL2⁺ dDCs than in CD103⁺ dDCs. Transfer of MGL2⁺ dDCs but not CD103⁺ dDCs from FITC-sensitized mice induced a Th2-type immune response in vivo in a model of contact hypersensitivity. Targeting MGL2⁺ dDCs with a rat monoclonal antibody against MGL2 efficiently induced a humoral immune response with Th2-type properties, as determined by the antibody subclass. We propose that the properties of MGL2⁺ dDCs, are complementary to those of CD103⁺ dDCs and skew the immune response toward a Th2-type response.

Strong induction of AIM2 expression in human epidermis in acute and chronic inflammatory skin conditions

Absent in melanoma 2 (AIM2) is a double-stranded DNA receptor, and its activation initiates an interleukin-1 beta processing inflammasome. AIM2 is implicated in host defense against several pathogens, but could hypothetically also contribute to autoinflammatory or autoimmune diseases, such as is the case for NLRP3. Using thoroughly characterised antibodies, we analysed AIM2 expression in human tissues and primary cells. A strong epidermal upregulation of AIM2 protein expression was observed in several acute and chronic inflammatory skin disorders, such as psoriasis, atopic dermatitis, venous ulcera, contact dermatitis, and experimental wounds. We also found AIM2 induction by interferon-gamma in submerged and three-dimensional in vitro models of human epidermis. Our data highlight the dynamics of epidermal AIM2 expression, showing Langerhans cell and melanocyte-restricted expression in normal epidermis but a pronounced induction in subpopulations of epidermal keratinocytes under inflammatory conditions.

Airborne contact dermatitis to drugs

Contact dermatitis is defined as "airborne" when the causative factor is present in the environment and may determine irritative or allergic skin reactions. It is often work-related. In this review of the literature, we focus our attention on airborne contact dermatitis due to pharmaceutical compounds. Contact reactions to medications, often occupation-related, occur mainly in two exposed groups: employees of pharmaceutical industries involved in the production of the drugs and healthcare workers who use the drugs for therapeutic aims.

Cigarette smoke exposure inhibits contact hypersensitivity via the generation of platelet-activating factor agonists

Previous studies have established that pro-oxidative stressors suppress host immunity because of their ability to generate oxidized lipids with platelet-activating factor receptor (PAF-R) agonist activity. Although exposure to the pro-oxidative stressor cigarette smoke (CS) is known to exert immunomodulatory effects, little is known regarding the role of PAF in these events. The current studies sought to determine the role of PAF-R signaling in CS-mediated immunomodulatory effects. We demonstrate that CS exposure induces the generation of a transient PAF-R agonistic activity in the blood of mice. CS exposure inhibits contact hypersensitivity in a PAF-R-dependent manner as PAF-R-deficient mice were resistant to these effects. Blocking PAF-R agonist production either by systemic antioxidants or treatment with serum PAF-acetyl hydrolase enzyme blocked both the CS-mediated generation of PAF-R agonists and PAF-R-dependent inhibition of contact hypersensitivity (CHS) reactions, indicating a role for oxidized glycerophosphocholines with PAF-R agonistic activity in this process. In addition, cyclooxygenase-2 inhibition did not block PAF-R agonist production but prevented CS-induced inhibition of CHS. This suggests that cyclooxygenase-2 acts downstream of the PAF-R in mediating CS-induced systemic immunosuppression. Moreover, CS exposure induced a significant increase in the expression of the regulatory T cell reporter gene in Foxp3(EGFP) mice but not in Foxp3(EGFP) mice on a PAF-R-deficient background. Finally, regulatory T cell depletion via anti-CD25 Abs blocked CS-mediated inhibition of CHS, indicating the potential involvement of regulatory T cells in CS-mediated systemic immunosuppression. These studies provide the first evidence, to our knowledge, that the pro-oxidative stressor CS can modulate cutaneous immunity via the generation of PAF-R agonists produced through lipid oxidation.

[Hymenoptera venom allergy. Analysis of double sensitization to wasp and bee venom in own material--diagnosis and classification for immunotherapy]

According to scientific societies guidelines the indication for venom immunotherapy is based on the clinical history of the patient. Diagnostic tests, like skin prick test or specific IgE serum estimation are conduct to prove IgE dependent mechanism of allergy and insect identification. Recent guidelines indicates for group of patients with severe systemic reactions as a candidates for diagnostic testing and in consequence for immunotherapy. In some countries diagnostic tests are also performed in patient who have a history of large local reactions, if they are considered as a candidates for immunotherapy. Double sensitization in cases of patients unable to identify the culprit insect is a diagnostic and therapeutic problem. In our group of patients (n = 113) we confirmed the double sensitization in 30% cases. The addition of a major allergen labeling reduced the number of people actually double-sensitized to 8.84%. It was observed that in patients who are not able to identify insect double sensitization phenomenon is particularly frequent as much as 45.5% and in the determination of the major allergens in 18.2%. Such patients needed detailed diagnosis and in many cases the use of two vaccines to conduct immunotherapy.

Immunotoxicity and allergic potential induced by topical application of dimethyl carbonate (DMC) in a murine model

Dimethyl carbonate (DMC) is an industrial chemical, used as a paint and adhesive solvent, with the potential for significant increases in production. Using select immune function assays, the purpose of these studies was to evaluate the immunotoxicity of DMC following dermal exposure using a murine model. Following a 28-day exposure, DMC produced a significant decrease in thymus weight at concentrations of 75% and greater. No effects on body weight, hematological parameters (erythrocytes, leukocytes, and their differentials), or immune cell phenotyping (B-cells, T-cells, and T-cell sub-sets) were identified. The IgM antibody response to sheep red blood cell (SRBC) was significantly reduced in the spleen but not the serum. DMC was not identified to be an irritant and evaluation of the sensitization potential, conducted using the local lymph node assay (LLNA) at concentrations ranging from 50-100%, did not identify increases in lymphocyte proliferation. These results demonstrate that dermal exposure to DMC induces immune suppression in a murine model and raise concern about potential human exposure and the need for occupational exposure regulations.

Contact hypersensitivity models in mice

The contact hypersensitivity (CHS) reaction is commonly utilized to study cell-mediated host immune responses to epicutaneously applied allergens. This reaction is divided into two distinct phases, the afferent phase and the efferent phase. During the afferent phase of this model, mice are exposed to a contact allergen, which is typically a hapten that is applied to a location distal to the site of elicitation. Following a brief intermission, mice are reexposed to the contact allergen during the elicitation phase at a site proximal to the location of sensitization. In mice, the pinna of the ear is typically utilized to evaluate the elicitation phase. While the CHS reaction is typically utilized to study Th1-mediated immune responses, it is now evident that Th2 and Th17 cells also contribute during the elicitation phase of the model. Likewise, in humans, elevated immune responses to contact allergens are associated with a variety of atopic diseases. Here, we describe a common protocol for the induction and assessment of the CHS reaction in mice.

Patch test reactions to metal salts in patients with different types of dermatitis

Metal allergies can be a clinical problem, especially in atopic individuals. This study is unique and contributes with new knowledge in everyday life skin care of irritant and atopic dermatitis patients. The aim of the study was to determine the frequency of positive patch test reactions to metal contact allergens (potassium dichromate, cobalt chloride, nickel sulfate, white mercury precipitate) in patients diagnosed with allergic contact dermatitis, irritant contact dermatitis, and atopic dermatitis. Between 2007 and 2011, patch testing was performed in 2185 patients according to the International Contact Dermatitis Research Group technique. Study results showed statistically significant differences in patch test responses to 2 allergens, nickel sulfate (χ(2)=24.22; p<0.001) and cobalt chloride (χ(2)=22.72; p<0.001). Nickel sulfate was the most common allergen in allergic contact dermatitis and atopic dermatitis, while for irritant contact dermatitis the most common allergen was cobalt chloride. Among the 4 tested metal allergens, the most common and relevant was nickel sulfate (χ(2)=17.25; p<0.004), found in almost all study subjects. In conclusion, the increased awareness of allergens and their potential sources may help limit the use of these chemicals in consumer product manufacturing.

Attenuated Bordetella pertussis BPZE1 protects against allergic airway inflammation and contact dermatitis in mouse models

BACKGROUND

We previously reported that prior nasal administration of highly attenuated Bordetella pertussis BPZE1 provides effective and sustained protection against lethal challenge with influenza A viruses. The protective effect was mediated by suppressing the production of major pro-inflammatory mediators. To further explore the anti-inflammatory properties of BPZE1, we investigated the effect of BPZE1 nasal pretreatment on two mouse models of allergic disease, allergic airway inflammation, and contact hypersensitivity (CHS).

METHODS

Allergic reactions were induced in mice nasally pretreated with live attenuated BPZE1 bacteria using the ovalbumin (OVA)-induced allergic airway inflammation and dinitrochlorobenzene (DNCB)-induced CHS models.

RESULTS

Prior BPZE1 nasal treatment suppressed OVA-induced lung inflammation and inflammatory cell recruitment and significantly reduced IgE levels and cytokine production. Similarly, BPZE1 nasal pretreatment markedly inhibited ear swelling, skin inflammation, and production of pro-inflammatory cytokines in the DNCB-induced CHS model. For both models, we showed that BPZE1 pretreatment does not affect the sensitization phase. Upon challenge, BPZE1 pretreatment selectively reduced the level of cytokines whose production is increased and did not affect the basal level of other cytokines. Together, our observations suggest that BPZE1 pretreatment specifically targets those cytokine-producing effector cells that are recruited and involved in the inflammatory reaction.

CONCLUSION

Our study demonstrates the broad anti-inflammatory properties of the attenuated B. pertussis BPZE1 vaccine candidate and supports its development as a promising agent to prevent and/or treat allergic diseases.

CD8+ T cell migration to the skin requires CD4+ help in a murine model of contact hypersensitivity

The relative roles of CD4+ and CD8+ T cells in contact hypersensitivity responses have not been fully solved, and remain an important question. Using an adoptive transfer model, we investigated the role of the respective T cell subset. Magnetic bead separated CD4+ and CD8+ T cells from oxazolone sensitized C57BL/6 mice were transferred into RAG−/− mice, followed by hapten challenge and analysis of inflammatory parameters at 24 hours post exposure. The CD4+ T cell recipient mice developed partial contact hypersensitivity responses to oxazolone. CD8+ T cells caused significant amplification of the response in recipients of both CD4+ and CD8+ T cells including ear swelling, type 1 inflammatory mediators, and cell killing. Unexpectedly, CD8+ T cells were not sufficient to mediate contact hypersensitivity, although abundantly present in the lymph nodes in the CD8+ T cell reconstituted mice. There were no signs of inflammation at the site of hapten exposure, indicating impaired recruitment of CD8+ T cells in the absence of CD4+ T cells. These data show that CD4+ T cells mediate contact hypersensitivity to oxazolone, but CD8+ T cells contribute with the most potent effector mechanisms. Moreover, our results suggest that CD4+ T cell function is required for the mobilization of CD8+ effector T cells to the site of hapten exposure. The results shed new light on the relative importance of CD4+ and CD8+ T cells during the effector phase of contact hypersensitivity.

Role of Th17 in the pathogenesis of cutaneous inflammatory diseases

Th17 cells are a new T-cell subtype characterized by the capability of producing IL-17. They are reported to be involved in a wide range of cutaneous immune-mediated conditions and, particularly in this review, we sought to elucidate the Th17 role in the pathogenesis of some common inflammatory diseases including psoriasis, allergic contact dermatitis and atopic dermatitis.

Quercetin is more effective than cromolyn in blocking human mast cell cytokine release and inhibits contact dermatitis and photosensitivity in humans

Mast cells are immune cells critical in the pathogenesis of allergic, but also inflammatory and autoimmune diseases through release of many pro-inflammatory cytokines such as IL-8 and TNF. Contact dermatitis and photosensitivity are skin conditions that involve non-immune triggers such as substance P (SP), and do not respond to conventional treatment. Inhibition of mast cell cytokine release could be effective therapy for such diseases. Unfortunately, disodium cromoglycate (cromolyn), the only compound marketed as a mast cell "stabilizer", is not particularly effective in blocking human mast cells. Instead, flavonoids are potent anti-oxidant and anti-inflammatory compounds with mast cell inhibitory actions. Here, we first compared the flavonoid quercetin (Que) and cromolyn on cultured human mast cells. Que and cromolyn (100 µM) can effectively inhibit secretion of histamine and PGD(2). Que and cromolyn also inhibit histamine, leukotrienes and PGD(2) from primary human cord blood-derived cultured mast cells (hCBMCs) stimulated by IgE/Anti-IgE. However, Que is more effective than cromolyn in inhibiting IL-8 and TNF release from LAD2 mast cells stimulated by SP. Moreover, Que reduces IL-6 release from hCBMCs in a dose-dependent manner. Que inhibits cytosolic calcium level increase and NF-kappa B activation. Interestingly, Que is effective prophylactically, while cromolyn must be added together with the trigger or it rapidly loses its effect. In two pilot, open-label, clinical trials, Que significantly decreased contact dermatitis and photosensitivity, skin conditions that do not respond to conventional treatment. In summary, Que is a promising candidate as an effective mast cell inhibitor for allergic and inflammatory diseases, especially in formulations that permit more sufficient oral absorption.

Cytip regulates dendritic-cell function in contact hypersensitivity

Cytohesin-interacting protein (Cytip) is induced during dendritic cell (DC) maturation and in T cells upon activation. It has also been shown to be involved in the regulation of immune responses. Here, we evaluated the functional consequences of Cytip deficiency in DCs using Cytip knockout (KO) mice. No difference in DC subpopulations in the skin draining lymph nodes (LNs) was found between Cytip KO mice and their wild-type counterparts, excluding a role in DC development. To investigate the function of Cytip in DCs in vivo, we used 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) as a model system. In the sensitization as well as in the elicitation phase, DCs derived from Cytip KO mice induced an increased inflammatory reaction indicated by more pronounced ear swelling. Furthermore, IL-12 production was increased in Cytip KO bone marrow-derived DCs (BMDCs) after CpG stimulation. Additionally, Cytip-deficient DCs loaded with ovalbumin induced stronger proliferation of antigen-specific CD4(+) and CD8(+) T cells in vitro. Finally, migration of skin DCs was not altered after TNCB application due to Cytip deficiency. Taken together, these data suggest a suppressive function for Cytip in mouse DCs in limiting immune responses.

Systemic immunomodulatory effects of topical dinitrochlorobenzene (DNCB) in rats. Activity of peripheral blood polymorphonuclear cells

Topical application of dinitrochlorobenzene (DNCB) is employed in the immunotherapy of skin diseases. Activation of T-cell mediated immune responses (Th1/type1) is the supposed mechanism of the clinical effect of DNCB, but there are no data concerning innate/inflammatory mechanisms. In this study, the effect of repeated topical DNCB application on peripheral blood polymorphonuclear (PMN) leukocytes has been examined in two rat strains which differ in the propensity to mount Th1/type1 or Th2/type2 responses. The dynamics of changes in PMN numbers and effector activities (respiratory burst, nitric oxide production and myeloperoxidase content), as well as in adhesion and TNF-α production following the rat skin sensitization with low (0.4%) and high (4%) DNCB doses were measured. Both priming and activation of PMNs were observed following skin sensitization with DNCB, with dose-dependent as well as time-dependent differences in some PMN activities. Obtained data might be relevant for understanding the immune mechanisms of topical DNCB therapy.

Structure-activity relationships and drug allergy

Structure-activity relationships (SARs) refer to the relation between chemical structure and pharmacologic activity for a series of compounds. Since the pioneering work of Crum-Brown and Fraser in 1868, they have been increasingly used in the pharmaceutical, chemical and cosmetic industries, especially for drug and chemical design purposes. Structure-activity relationships may be based on various techniques, ranging from considerations of similarity or diversity of molecules to mathematical relationships linking chemical structures to measured activities, the latter being referred to as quantitative SAR or QSAR. This review aims at briefly reviewing the history of SARs and highlighting their interest in delayed and immediate drug allergy using selected examples from the literature. Studies of SAR are commonly conducted in the area of contact dermatitis, a delayed hypersensitivity reaction, to determine the allergenic potential of a given compound without animal testing. In immediate, immunoglobulin E-mediated drug hypersensitivity, this kind of approach remains rather confidential. It has been mainly applied to neuromuscular blocking drugs (muscle relaxants) and betalactam antibiotics (penicillins, cephalosporins). This review shows that SARs can prove useful to (i) predict the allergenic potential of a chemical or a drug, (ii) help identify putative antigenic determinants for each patient or small group of patients sharing the same cross-reactivity pattern, and (iii) predict the likelihood of adverse reactions to related molecules and select safe alternatives.

Isolated contact urticaria caused by immunoglobulin E-mediated fish allergy

Fish is a common cause of food allergy. The reactions usually occur after its ingestion. In most immunoglobulin E-mediated reactions, the allergens are gastroresistant and heat-stable proteins of low molecularweight (parvalbumin). On the other hand, isolated contact urticaria following the handling of raw fish but without symptoms after its ingestion was found among cooks and professional fish handlers. In these cases, the fish allergens are gastrosensitive and thermolabile, as demonstrated by the decrease in the diameter of the wheal in the skin-prick test using cooked fish. To the best of our knowledge isolated fish contact urticaria in children has not been previously reported. We analyze the features of three pediatric cases of contact urticaria from cod (one of them was sensitized to parvalbumin), with tolerance after ingestion of this fish on oral food challenge.

Molecular allergology in practice: an unusual case of LTP allergy

The authors describe an unusual case of LTP allergy. A 35 years old patient presented repeated episodes of angiooedema after food intake and complained 10 years ago of contact urticaria and rhinoconjunctivitis when exposed to cannabis leaves and to marijuana smoke. The suspected responsible foods, such as wheat flour in bread, are known to contain LTR Oral syndrome occurred after ingestion of walnuts. Cutaneous tests confirmed immediate responses to several flours and nuts and also to cannabis leaf and flower. A few months later he had similar accidents following peach ingestion and drinking of beer and several wines which all induced positive skin tests. Serological investigations using ImmunoCAP and ISAC microarray confirmed IgE positivity for n Pru p3, r Cor a 8 and n Art v3. It was assumed that sensitization to LTP, the major allergen of cannabis, was responsible of the primary sensitization and induced further LTP food allergies.