IgE-mediated Skin Reaction Research Articles

Characterization of IgE-binding proteins in the salivary glands of Simulium nigrogilvum (Diptera: Simuliidae).

Simulium dermatitis is an IgE-mediated skin reaction in animals and humans caused by the bites of black flies. Although Simulium nigrogilvum has been incriminated as the main human-biting black fly species in Thailand, information on its salivary allergens is lacking. Salivary gland extract of S. nigrogilvum females was subjected to sodium dodecylsulfate-polyacrylamide gel electrophoresis, and the separated components were applied onto nitrocellulose membranes for immunoblotting, which was performed by probing the protein blots with sera from 17 individuals who were allergic to the bites of S. nigrogilvum. IgE-reactive protein bands were characterized further by liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Nine protein bands (79, 42, 32, 25, 24, 22, 15, 13, and 11kDa) were recognized in the serum of the subjects. Four of the nine protein bands (32, 24, 15, and 11kDa) showed IgE reactivity in all (100%) of the tested sera, and they were identified as salivary secreted antigen 5-related protein, salivary serine protease, erythema protein, and hypothetical secreted protein, respectively. Three other proteins, salivary serine protease (25kDa), salivary D7 secreted protein (22kDa), and hypothetical protein (13kDa), reacted with > 50% of the sera. The relevance of the identified protein bands as allergens needs to be confirmed by using pure recombinant proteins, either in the in vivo skin prick test or in vitro detection of the specific IgE in the serum samples of allergic subjects. This will be useful for the rational design of component-resolved diagnosis and allergen immunotherapy for the allergy mediated by the bites of black flies.

Thermographic assessment of skin prick tests in comparison with the routine evaluation methods.

IntroductionThe skin prick test is still the first and basic procedure in the diagnosis of allergic diseases. The possibility of using a sensitive thermographic method supported by the mathematical model for the assessment of skin test results will be highlighted in the studies.AimTo compare the proposed approach with routine planimetric and thermographic methods.Material and methodsA mathematical model of allergic reaction was developed. Simplifying assumptions of the IgE-mediated skin reaction is the essence of the model. Investigations were performed in a group of 40 patients.ResultsUsing the spatio-temporal evolution of temperature distributions, the ratios of the histamine released from mast cells to the control histamine were determined. The obtained values very well correlate with the standard evaluation of skin prick tests (correlation coefficient = 0.98).ConclusionsThe proposed method of skin test evaluation presents several advantages. The continuous acquisition of data provides the monitoring of time course of the allergic response. The transport of mediator and its concentration were distinctly discriminated, which may be diagnostically useful, especially for abnormal cases. The high sensitivity of the method enables studying patients regardless of age and skin sensitivity.

Hydroxyzine and cetirizine pharmacokinetics and pharmacodynamics after oral and intravenous administration of hydroxyzine to healthy dogs

Pharmacokinetic parameters of hydroxyzine and its active metabolite cetirizine were determined after oral and intravenous administration of 2 mg kg(-1) of hydroxyzine to six healthy dogs. Plasma drug levels were determined with high-pressure liquid chromatography. Pharmacodynamic studies evaluated the suppressive effect on histamine and anticanine IgE-mediated cutaneous wheal formation. Pharmacokinetic and pharmacodynamic correlations were determined with computer modelling. The mean systemic availability of oral hydroxyzine was 72%. Hydroxyzine was rapidly converted to cetirizine regardless of the route of administration. The mean area-under-the-curve was eight and ten times higher for cetirizine than hydroxyzine after intravenous and oral dosing, respectively. After oral administration of hydroxyzine, the mean peak concentration of cetirizine was approximately 2.2 microg mL(-1) and that of hydroxyzine 0.16 microg mL(-1). The terminal half-life for cetirizine varied between 10 and 11 h after intravenous and oral administration of hydroxyzine. A sigmoidal relationship was fit to the data comparing cetirizine plasma concentration to wheal suppression. Maximum inhibition (82% and 69% for histamine and anticanine IgE-mediated skin reactions, respectively) was observed during the first 8 h, which correlated with a plasma concentration of cetirizine greater than 1.5 microg mL(-1). Pharmacological modelling suggested that increasing either hydroxyzine dosages or frequencies of administration would not result in histamine inhibition superior to that obtained with twice daily hydroxyzine at 2 mg kg(-1). In conclusion, there was rapid conversion of hydroxyzine to cetirizine. The reduction of wheal formation appeared almost entirely due to cetirizine. Pharmacodynamic modelling predicted that maximal antihistamine effect would occur with twice daily oral administration of hydroxyzine at 2 mg kg(-1).

Milk-induced urticaria is associated with the expansion of T cells expressing cutaneous lymphocyte antigen

Background: Two forms of IgE-mediated skin reactions, atopic dermatitis (AD) and urticaria, have been associated with milk allergy. The reason for these distinct reactions is poorly understood. T cells expressing cutaneous lymphocyte antigen (CLA), a unique skin-homing receptor, are known to play an important role in AD. In contrast, the role of lymphocytes in patients with milk-induced urticaria is unclear. Objective: The expression of the skin-specific homing receptor CLA after in vitro milk protein—specific stimulation was investigated to determine whether T-lymphocyte homing to the skin plays a role in food-induced urticaria. Methods: Fourteen patients with milk-induced urticaria but no evidence of AD were included in the study and compared with 6 children with milk-induced AD, 6 children with milk-induced gastrointestinal diseases, and 6 nonatopic and 6 atopic individuals without milk allergy. PBMCs were cultured in the presence or absence of caseins or tetanus toxoid. T-cell proliferation was determined, and T-cell phenotyping was performed by means of flow cytometry with anti-CD4, anti-CD8, and anti-CLA mAbs. Results: After in vitro stimulation with caseins, PBMCs from patients with milk-induced urticaria and AD had a significantly greater percentage of CD4+ T cells expressing CLA than patients with milk-induced gastrointestinal symptoms and atopic or nonatopic control subjects. After tetanus stimulation in vitro, no significant difference between the groups was observed. T cells from both patients with milk-induced urticaria and control subjects proliferated well in response to caseins and tetanus. Conclusion: Lymphocytes expressing CLA are selectively activated in patients with milk-induced urticaria and may play an important role in the pathogenesis of this disease. Expression of CLA is not unique to milk-induced inflammation in the skin of patients with AD and milk allergy. (J Allergy Clin Immunol 2002;109:688-93.)

Effects of adjuvants on the immune response to allergens in a murine model of allergen inhalation: cholera toxin induces a Th1-like response to Bet v 1, the major birch pollen allergen.

Based on the fact that type I allergies are frequently elicited by inhalant allergens, we have established a model of aerosol inhalation leading to allergic sensitization in BALB/c mice. Using this model we studied the effects of aluminium hydroxide (Al(OH)3), known to enhance IgE antibody responses, compared with cholera toxin (CT), a potent mucosal adjuvant, on the immune response to birch pollen (BP) and its major allergen Bet v 1. Two groups of BALB/c mice were either systemically immunized with recombinant Bet v 1 in Al(OH)3 and subsequently aerosol exposed to BP allergen, or aerosolized with BP and CT. IgE-mediated skin reactions were only elicited in the mice which had received Bet v 1/Al(OH)3. Allergen-specific serum IgE and IgG1 antibodies dominated in the Al(OH)3 group, IgG2a antibody levels to BP and rBet v 1 were markedly higher in the sera of mice exposed to CT with the allergen. IgA antibodies were only detected in the bronchial lavage of the CT-treated group. Moreover, the latter group displayed consistently higher T cell proliferative responses to BP and interferon-gamma production in vitro. Thus, the systemic immunization with rBet v 1 in Al(OH)3 before inhalation of the BP extract promoted a Th2-like immune response, while CT mixed with the aerosolized BP extract rather induced a Th1-like immune response. In an attempt to reverse these ongoing immune responses we could achieve a shift towards a Th0 response. Immunization with BP extract without adjuvant treatment led to undetectable antibody or cellular immune responses. We conclude from the present study that the induction of an immune response to BP allergen after aerosol inhalation can be directed towards a Th1- or a Th2-like response. Once established, the immune response can be modulated.

Therapeutic potential of a novel synthetic selectin blocker, OJ-R9188, in allergic dermatitis.

1. We investigated the ability of a newly synthesized sugar derivative, OJ-R9188, [N-(2-tetradecylhexadecanoyl)-O-(L-alpha-fucofuranosyl)-D-seryl]-L-glutamic acid 1-methylamide 5-L-arginine salt, to block binding of selectins to their ligands in vitro and inhibit the infiltration of leukocytes in vivo. 2. OJ-R9188 prevented the binding of human E-, P- and L-selectin-IgG fusion proteins to immobilized sialyl Lewis(x) (sLe(x))-pentasaccharide glycolipid, with IC(50) values of 4.3, 1.3, and 1.2 microM, respectively. 3. In a mouse model of thioglycollate-induced peritonitis, OJ-R9188 at 10 mg kg(-1), i.v. inhibited neutrophil accumulation in the peritoneal cavity. In the IgE-mediated skin reaction, OJ-R9188 at 3 and 10 mg kg(-1), i.v. significantly inhibited extravasation of neutrophils and eosinophils into the inflammatory sites and at 10 mg kg(-1), i.v. also inhibited infiltration caused by picryl chloride-induced delayed-type hypersensitivity in mice. These results suggest that OJ-R9188 may be a useful selectin blocker, with activity against human and mouse E-, P- and L-selectins in vitro and in vivo, and that blocking selectin-sLe(x) binding is a promising strategy for the treatment of allergic skin diseases.

Role of selectins on IgE-mediated skin reaction.

Selectins play an important role on leukocytes infiltration into inflammatory tissues. To understand the role of selectins, we investigated the effects of selectin-IgG chimeras and anti selectin antibodies on the murine IgE-mediated skin inflammation model. Biphasic skin reactions were induced by intradermal challenge with ovalbumin (OA) to ears of actively sensitized mice. This reaction was characterized by immediate and late phase responses observed as which were induced via a rapid increase in capillary permeability and leukocyte infiltration, respectively. The expression of E-selectin mRNA was significantly increased to reach its highest level at 2 h after OA challenge. E-, P-, and L-selectin-IgG chimeras inhibited the late phase responses, i.e. ear swelling, neutrophil infiltration and eosinophil infiltration at 24 h after OA challenge in a dose-dependent manner at dose range of 0.1 - 10 mg kg(-1), i.v. Antiselectin antibodies did not inhibit the increase of ear swelling. But anti E- and P-selectin antibodies significantly inhibited neutrophil infiltration and eosinophil infiltration. These results indicate that selectins play an important role on the late phase response of the murine IgE-mediated skin inflammation model by mediating inflammatory cell adhesion to endothelium.

Effect of Shimotsu-to (a Kampo medicine, Si-Wu-Tang) and its constituents on triphasic skin reaction in passively sensitized mice

Previous studies have reported that mice passively sensitized with anti-DNP (dinitrophenol) IgE antibody exhibited IgE-mediated skin reaction with an immediate phase response (IPR) at 1 h and a late phase response (LPR) at 24 h after the challenge of DNFB (dinitrofluorobenzene). We recently found that a third phase inflammatory reaction with intense and persisting infiltration of eosinophils, named very late phase response (vLPR), was induced by DNFB challenge peaking at 8 days. In this study, we examined the effects of a Kampo medicine, Shimotsu-to (Si-Wu-Tang), and its constituent crude drugs on triphasic skin reaction in passively sensitized mice. Shimotsu-to inhibited ear swelling in LPR and vLPR after DNFB challenge in a dose-dependent manner, and slightly diminished the scratching behavior considered to be associated with pruritis in IPR. The inhibitory effect on LPR and vLPR was partly due to Cnidii Rhizoma (Senkyu) in Shimotsu-to formulation, especially its fraction 5 containing cnidilide. On the other hand, Angelicae Radix (Toki) rather than Cnidii Rhizoma (Senkyu) in Shimotsu-to, inhibited the scratching behavior, although it did not inhibit the ear swelling in IPR. These findings indicate that the Shimotsu-to formulation is useful for the inhibition of cutaneous inflammatory diseases.

Heterogeneity of human skin mast cells and human basophils. I. Pharmacological experiments with activators and inhibitors of protein kinase C.

Skin mast cells and basophilic leukocytes are known as key elements of acute and subacute IgE-mediated immune responses of the skin. The present paper investigated pharmacological aspects of signal transduction pathways of both cell types using activators and inhibitors of protein kinase C (PKC). The nonselective inhibitor K252a suppressed Fc epsilon RI-mediated histamine release from basophils and skin mast cells dose-dependently with IC50 values of 0.01 and 0.28 mumol/l. However, preincubation of both cell populations with kinase inhibitors showing in vitro selectivity for PKC (Ro 31-7549, calphostin C, GF 109203X) revealed a distinct modulation of cell response: IgE-mediated mediator release was inhibited only in skin mast cells, whereas in experiments with basophils a concentration-dependent potentiation of exocytosis was observed. Further evidence for heterogenous biochemical signals following activation of both cell types derived from studies with the phorbol ester TPA. With respect to acute and late-phase IgE-mediated skin reactions, we suggest that distinct signal transduction mechanisms at the level of PKC (isozymes) in basophils and skin mast cells might reflect their functional heterogeneity.

Effects of fractions of skin chamber fluids from human allergic reactions on neutrophil activation

Using a skin chamber approach, we have found an accumulation of activated polymorphonuclear neutrophils (PMNs) and their released components in the sites of developing human late-phase IgE-mediated skin reactions.’ We recently found that the overlying chamber fluid obtained during the first hour of pollen antigen challenge could directly stimulate resting blood PMNs in vitro.’ The nature of the stimulatory component or components in such fluids is not known. Attempts at characterization are limited by the amount of fluid that can be obtained from an individual subject. A reasonable initial characterization would be the determination of in vitro effects of ultrafiltration fractions of such fluids on blood neutrophils.

Comparisons of inflammatory responses in IgE-mediated and codeine-induced skin reactions

The allergic inflammatory cell response has been shown to be an important component in allergic rhinitis and some skin disorders.‘* ’ Using skin chamber and skin biopsy approaches we have found that: (1) gross late-phase reactions (LPRs) occur commonly in the sites of immediate IgE-mediated skin reactions; and (2) continued antigen challenge induces a prominent local accumulation of granulocytes during the next several hours when LPRs are developing.3 Because such LPRs to antigen challenge are practically always preceded by prominent immediate wheal and flare, it is believed that the pathogenesis of LPRs depends on prior mast cell activation. However, LPRs occur very infrequently in the sites of previous immediate wheal and flare reactions to codeine,4 even though we have recently observed very prominent release of histamine into overlying skin chambers during the first hour of codeine challenge.5 To enhance our understanding of the reasons for the different patterns of gross human skin responses to codeine and antigens we obtained biopsy specimens 6 hours after intradermal injection of antigen and codeine to compare inflammatory cell responses during developing LPRs .

Effects of skin-chamber fluids from human allergic reactions on neutrophil activation

We have found activated neutrophils (PMNs) in skin chambers overlying the site of ongoing human allergic reactions. To determine whether this activation is due to component(s) released early in these IgE-mediated reactions, we investigated the in vitro effects of skin chamber fluids (CF) on resting blood PMNs. These skin CF had been previously obtained, at different time periods, at pollen-antigen-challenged or buffer-control-challenged sites in sensitive human subjects. PMNs incubated with CF obtained during the first hour of antigen challenge (first-hour CF) generated significantly more superoxide (O2-) than spontaneous production (p less than 0.001) and more than PMNs incubated with first-hour buffer-site CF (p less than 0.002). A pattern similar to O2- generation was observed in lactoferrin secretion during the incubation of the three cell aliquots described above (p less than 0.001). After these incubations, the subsequent responsiveness of the PMNs present in the cell buttons to opsonized zymosan, a PMN activator, was assessed. PMNs previously incubated with first-hour CF generated significantly more net O2- in response to opsonized zymosan than did PMNs previously incubated with first-hour buffer-site CF (p less than 0.001) or buffered saline (p less than 0.001). Again, a similar difference in the patterns of net lactoferrin secretion was observed (p less than 0.02). These events were not associated with PMN damage. Analogous studies with CF previously obtained during the second- to first-hour of antigen or buffer challenge stimulated much less than first-hour CF. We conclude that one or more components released early in IgE-mediated skin reactions can activate PMNs. The nature of the activating component(s) is unknown, with no evidence of activation by histamine, antigen, or other components found to date in first-hour CF.

IgE-Mediated Skin Reaction Among Asthmatic Children in Riyadh

Fifty-five asthmatic children aged 6-13 years attending a pediatric allergy clinic were skin tested with a panel of 35 inhalant commercial allergens. The allergen extracts were grouped into pollen including trees, grasses and weeds, fungal spores, insect, animal and other indoor allergens. Thirty-five (63.6%) of the asthmatic children had one or more positive skin reactions. Reactions were most common, and strongest to the indoor and animal panel and to pollens. Fungal reactions were less common and weaker. This represents a lower proportion of skin test-positive asthmatic children than other Western countries. This might relate either to the presence of asthma without atopy, lack of exposure to potential allergens, or lack of appropriate antigens relevant to the disease in the skin test panel.