Inverse correlation of domestic exposure to Dermatophagoides pteronyssinus antigen patch test reactivity in patients with atopic dermatitis

BACKGROUND: In recent years considerable interest in the pathogenetic role of aeroallergens exacerbating atopic dermatitis (AD) has emerged. The 'atopy patch test' with aeroallergens was introduced by Platts-Mills et al. as an experimental model and as a diagnostic tool. However, its relevance for the clinical manifestation of AD is still not clear. OBJECTIVE: We asked whether there is a relationship between the individual antigen exposure to the major allergen of Dermatophagoides pteronyssinus (Der p 1) and the immunological markers of sensitization to Der p 1 or the clinical severity of AD. METHODS: We investigated 92 patients with moderate to severe AD. For clinical evaluation the SCORAD severity score was used. Patch tests were performed with purified Der p 1. Specific IgE was measured by a commercial assay. Der p 1 exposure was quantified in a sample of the patient's mattress dust by using a commercial ELISA. RESULTS: No correlation between SCORAD, Der p 1 exposure and RAST could be established. However, there was an unexpected significant inverse correlation between the quantity of mite antigen in the mattress dust and patch test reactivity. Patients with a high antigen load (> 25 microg/g) mostly had a negative patch test. Also, when Der p 1 was correlated to the mattress area (m2) in this group all patch tests were negative. A possible explanation could be that continuous exposure of the skin to house dust mite allergen Der p 1 may induce a down-regulation of the skin immune system of patients with AD. CONCLUSION: Although the mechanism of this phenomenon is presently unknown, our study shows that a positive allergen patch test alone should not be an indication to undertake allergen exclusion measures in AD patients.     

Intradermal skin tests with Dermatophagoides pteronyssinus in asthmatic children: correlation with specific IgE and bronchial provocation tests

The purpose of the present study was to compare the results of the skin tests, the specific IgE levels and bronchial provocation tests in a group of sensitive asthmatic children with a Dermatophagoides pteronyssinus extract standardized by the RAST inhibition method. Skin tests showed a positive ‘end point’ in twelve children of 0.5 U/ml antigen; in eleven 5 U/ml; seven of 50 U/ml; six of 500 U/ml. Specific IgE was present in thirty-three children (92%). A close relationship between positive skin tests and serum IgE levels was found. Bronchial provocation tests were positive in twenty-eight children (78%): eight children with both positive RAST and positive skin tests had negative bronchial provocation tests.     

A double-blind controlled trial of hyposensitization to Dermatophagoides pteronyssinus in children with atopic eczema

A double-blind controlled trial of hyposensitization with tyrosine-adsorbed Dermatophagoides pteronyssinus vaccine in 24 children with atopic eczema and immediate hypersensitivity to D. pteronyssinus failed to demonstrate superiority over placebo after a standard 8 month course of treatment. In a second phase, children initially administered active treatment were randomly allocated to continue with active treatment or switched to placebo for a further 6 months. The clinical scores suggest that prolonged hyposensitization may be more effective than placebo but the numbers were too small to permit confident conclusions. A dramatic placebo effect may have served to conceal any additional therapeutic effect from active treatment.     

几种户尘螨过敏原点刺液的临床评价

评价户尘螨过敏原点刺皮试液用于诊断和筛查尘螨过敏的意义。方法：对219例患者进行户尘螨过敏原点刺试验和户尘螨sIgE检测。点刺试验所用点刺液为本课题组研制的点刺液（A 组）、ALK公司的户尘螨点刺液（B组）和ALK公司的混合螨（户尘螨和粉尘螨）点刺液（C组）,以sIgE为诊断标准。统计分析采用SPSS 11．0软件,对三组户尘螨过敏原点刺试验进行ROC曲线评价。结果：A、B和C组风团平均直径中位数为0.43cm、0.35cm和 0.28cm。所有入选者点刺试验后1h,A组有5例点刺试验后出现局部反应,2h左右自行缓解;有2例出现迟发反应,需1天左右才消退;B组和C组各有3例点刺试验后出现局部反应,B组和C组各有2例有迟发反应。所有患者均无局部皮疹、全身性不良反应。三组户尘螨过敏原点刺试验的ROC曲线下面积分别为0.765、0.801、0.782,说明户尘螨过敏原点刺皮试液对诊断户尘螨过敏具有较高准确性。以户尘螨sIgE为标准的点刺试验灵敏度和特异度：A、B 和C组点刺液的灵敏度分别为92.4％、87.0％和81.5％,特异度分别为60.6%、73.2%和74.8%。结论：户尘螨点刺液可作为用于尘螨过敏的诊断试剂,有良好的灵敏度和特异度,具有临床筛查和诊断意义。     

Sensitization to Dermatophagoides pteronyssinus and Blomia tropicalis extracts and recombinant mite allergens in atopic Thai patients

Mite surveys in Thailand indicated that Dermatophagoides pteronyssinus (Dp) is predominant, but so far there were no data available on Blomia tropicalis (Bt), which is prevalent in the Asia Pacific region. Skin prick testing (SPT) was performed in 40 atopic children, 45 atopic adults and 17 non-atopic volunteers. Skin reactions to Dp were found in 25/40 (62.5%) and 23/45 (51.1%); skin reactions to Bt were found in 15/40 (37.5%) and 18/45 (40%) in atopic children and adults, respectively. SPT to the major sensitizing allergens Der p 1, Der p 2, Der p 5, and Blo t 5 showed positive results in 14/40 (35%), 12/40 (30%), 1/40 (2.5%) and 4/40 (10%) of atopic children, and in 12/45 (26.7%), 13/45 (28.9%), 5/45 (11.1%), 6/45 (13.3%) of atopic adults, respectively. The results indicate that Dp is one of the major sources of allergy, while Bt is a minor one and that Der p 1 and Der p 2 are important mite allergens in Chiang Mai, Thailand.     

Trimodality of serum Dermatophagoides farinae-specific IgE RAST levels in atopic dermatitis patients.

Serum Dermatophagoides farinae-specific IgE RAST (DF IgE) levels were assayed in 122 atopic dermatitis patients at the first examination. From the statistical study, we found trimodality of the individual variability of serum DF IgE levels. We hypothesize that serum DF IgE levels may be controlled by a pair of allelic genes.     

Influence of hyposensitization with Dermatophagoides pteronyssinus extract on clinical score, total and specific IgE levels, and skin test in asthmatic patients

To evaluate the effects of immunotherapy on clinical response, on IgE serum level, on radioallergosorbent test (RAST), and on skin tests, a prospective study was performed by a follow-up of 73 asthmatic patients allergic for house dust during hyposensitization with Dermatophagoides pteronyssinus extract. No relationship could be found between the evolution of clinical score, skin tests and RAST, but 91% of the patients with a decreasing IgE serum level had satisfactory clinical results. Serial determinations of serum IgE levels during hyposensitization showed two patterns of evolution with a favourable prognostic value: a continuously decreasing serum IgE or a primary increase followed by a late decrease.     

Allergen specific immunotherapy for atopic dermatitis

PURPOSE OF REVIEW: To describe recent developments as well as the pros and cons of allergen specific immunotherapy as a putative therapeutic option for a subgroup of patients with atopic dermatitis. RECENT FINDINGS: The question whether specific immunotherapy would impair or improve the severity and course of atopic dermatitis has been a matter of debate for a long time. Double-blind placebo-controlled studies on the safety and efficacy of subcutaneous and sublingual specific immunotherapy in atopic dermatitis are rare; however, a systematic review of the literature on all published studies on specific immunotherapy in atopic dermatitis, together with the results of the most recent controlled studies, provides promising results. SUMMARY: The review discusses developments and recent advances in the field of specific immunotherapy as a causal therapy of sensitizations in atopic dermatitis. The most promising approaches, outlining putative immunologic as well as clinical changes which might go along with specific immunotherapy in atopic dermatitis patients, are highlighted. Further, we discuss how upcoming clinical studies and research could help to open new avenues for specific immunotherapy as a treatment for atopic dermatitis in the near future.     

Reduction of Staphylococcus aureus in atopic skin lesions with acid electrolytic water - a new therapeutic strategy for atopic dermatitis

The subjects studied were 22 pediatric patients newly diagnosed with atopic dermatitis (AD); 11 were treated with acid electrolytic water (AEW), which has a strong bactericidal activity (AEW group), and the other 11 with tap water (placebo group). AEW or tap water, 1 ml/cm² (body surface area), was sprayed on their skin lesions with a spray gun each twice a day for a week. There were no significant differences between the two groups in regard to sex, age, serum IgE, peripheral eosinophil counts, grading scores of AD, and duration of AD. The study was designed as a randomized, placebo-controlled, double-blind clinical trial. Colony counts of Staphylococcus aureus on skin lesions in the AEW group, both 3 min after spraying ( P < 0.05) and after 1 week of skin treatment ( P < 0.01), were significantly decreased as compared with colony counts before treatment, while there was no significant difference in the placebo group before and after treatment. Grading scores of AD also decreased in the AEW group ( P <0.01), but not in the placebo group. Both the subjects' guardians' evaluation and a referee physician's evaluation of treatment effect were significantly higher in the AEW group than in the placebo group ( P < 0.01). AEW may be potentially effective in preventing a staphylococcal chronic inflammation in AD because of its strong bactericidal activity.     

Dermatophagoides pteronyssinus specific IgM antibody and its complement activation in children with bronchial asthma

Western blotting analysis and ELISA were used to examine Dp specific IgM abs in the sera and sputa of bronchial asthmatic and non-atopic children. With Western blotting Dp specific IgM abs were detected binding diffusely to high molecular weight (greater than 65 kD) components of Dp extracts and from the intensities of the staining of the sera the asthmatic children were divided into two groups: an intensive staining and a faint staining group. The non-atopic children showed still fainter staining than the latter group. ELISA titers of Dp specific IgM abs in the intensive staining group were significantly higher than in the faint staining group and the non-atopic children (p less than 0.01). Dp specific IgM abs in sputa were also detected more intensively in asthma than in non-atopy by Western blotting. The hemolytic complement activities of the fresh sera were consumed when they were incubated with Dp extracts at 37 degrees C. The degree of consumption was significantly higher in the intensive staining group than in the faint staining group and the non-atopic children (p less than 0.05). High molecular weight fractions of Dp extracts were responsible for this complement inactivation. From these results we suspected that Dp specific IgM abs might react with high molecular weight components of Dp to induce complement activation by the classical pathway and might cause chronic inflammatory changes in the respiratory mucosa. This chronic inflammation might emphasize IgE mediated asthmatic reactions to cause late phase reactions or chronic asthma.     

Platelet activation in allergic asthma patients during allergen challenge with Dermatophagoides pteronyssinus

BACKGROUND: Animal models of allergic asthma indicate that intravascular platelet activation is necessary for the development of allergen-induced chronic airway inflammation. OBJECTIVE: To evaluate whether the development of a late asthmatic response (LAR) in allergic asthma patients challenged with a relevant allergen is consequent to platelet activation. METHODS: Thirty-three house dust mite sensitive asthmatic patients were challenged intrabronchially with Dermatophagoides pteronyssinus (Dp) extract. Twelve non-atopic healthy subjects (HC) were used as controls. Platelet count and plasma levels of beta-thromboglobulin (beta-TG), platelet factor-4 (PF-4) and soluble P-selectin (sP-selectin) were assessed before the challenge (T(0)) and 30 min (T(EAR)), 6 h (T(LAR)) and 24 h (T(24)) after the challenge. RESULTS: Eleven patients responded to allergen challenge with an isolated early asthmatic response (single responders, SR). In 22 patients dual asthmatic response was demonstrated (dual responders, DR). At T(0) neither the platelet count nor the mean plasma level of beta-TG in DR or SR were different from HC, the mean plasma level of PF-4 in SR was significantly greater than in HC (P=0.01) or DR (P=0.001), the mean plasma level of sP-selectin was significantly greater in DR than in HC (0.0002) but not statistically different from SR (P=0.055). A significant decrease in the platelet count and increase in the plasma level of all the studied markers was seen at T(EAR), which was followed by a gradual return to the baseline values in the SR. Elevated plasma levels of platelet activation markers and decreased platelet count were seen in the DR even at T(24). Strong correlation was found between the increase in plasma concentration of beta-TG at T(EAR) and the maximum fall in forced expiratory volume in 1 s at T(LAR) (r=-0.57; P=0.0006). CONCLUSION: In allergic asthma patients development of prolonged airway inflammation after allergen challenge is associated with intravascular platelet activation.     

T-cell sensitization to epitopes from the house dust mites Dermatophagoides pteronyssinus and Euroglyphus maynei

Background Dermatophagoides pteronyssinus and Euroglyphus maynei frequently occur in house dust but little is known about primary sensitization to the less abundant E. maynei. Objective To determine the occurrence of primary sensitization to E. maynei by T-cell responses and the crossreactivity to D. pteronyssinus. Methods The proliferative response ot peripheral blood cells to overlapping peptides from Derp I and Eur m 1 were measured as well as to peptides from Der f 1, an allergen not found in the study environment. Results The most frequent and strongest responses were to Der p 1 peptides especially in the region 105–133. However, 3/17 responders to mite peptides were stimulated predominantly by Eur m 1 peptides and a further two had their highest response to an Eur m 1 peptide. There was very little crossreactivity between Der p 1 and Eur m 1 peptides and very little response to peptides from Der f 1. Conclusion E. maynei group 1 allergens are a significant source of primary T-cell sensitization and have little T-cell crossreactivity with D. pteronyssinus or D. farinae.     

Skin-derived aeroallergen-specific T-cell clones of Th2 phenotype in patients with atopic dermatitis.

T-cell lines have been derived from aeroallergen-induced eczematous patch test sites of patients with atopic dermatitis (AD). Biopsy specimens were obtained 24 hours after allergen application to the skin, and only in vivo-activated T cells were propagated. From one patient, the T-cell lines were subcloned at 0.3 cells per well. With allergen-induced interleukin (IL) production, all clones tested (n = 13) were found to be specific for the allergen, producing IL-4 and granulocyte-macrophage-colony-stimulating factor. No IL-2 or interferon-gamma was found. The allergen-specific proliferative response of these clones, although the response was dependent on exogenous IL-2 or IL-4, also proved that all clones were allergen specific. Under optimal stimulation (aCD3 plus phorbol myristate acetate), 15% of the clones appeared to be of Th0 phenotype and 70% of Th2 phenotype. In 15% of the clones, IL-4 was produced in the absence of IL-2, IL-5, or interferon-gamma. Supernatants of all clones tested induced IgE production by B cells from normal non-atopic donors. The T-cell lines of the other patient demonstrated similar results; allergen-specific proliferation was dependent on exogenous IL-2 or IL-4 and stimulation with aCD3 plus phorbol myristate acetate demonstrated that the T cells in these lines were of the Th2 phenotype. In conclusion, our data reveal that, in AD, percutaneous sensitization to aeroallergens may occur and indicate that allergen-specific Th2 type T cells may be responsible for the high levels of (specific) IgE found in 80% of patients with AD.     

儿童特应性皮炎血清特异性IgE和斑贴试验结果的临床分析

目的:回顾性分析广州地区特应性皮炎(AD)患儿常见变应原,为AD预防和诊治提供依据.方法:ELISA检测138例AD患儿血清特异性IgE(sIgE),并分析其吸入组、食入组变应原;其中43例患儿同时接受了用于检测日常接触类变应原的皮肤斑贴试验,分析其结果分布特征.结果:吸入性特异性总IgE抗体检测结果阳性率为57.97...     

Development of an enzyme-linked immunosorbent assay for detection of IgE antibodies specific to Dermatophagoides pteronyssinus

Allergy to Dermatophagoides pteronyssinus was determined in 61 rhinitis patients using prick test (PT), enzyme-immunoassay (EIA) and enzyme-linked immunosorbent assay (ELISA). A total of 43 patients tested positive with PT. Forty six patients were positive when tested with EIA and ELISA. With PT as standard test, EIA was found to have 83.7% sensitivity and 44.4% specificity; ELISA had 81.4% sensitivity and 38.9% specificity. There was a linear relationship between absorbance values obtained by EIA and ELISA. The performance time was 8 hours, 24 hours and 30 minutes for ELISA, EIA and PT respectively. The cost per test for ELISA, EIA and PT was US$ 0.20, US$ 5.20 and US$ 0.14 respectively. It was concluded that ELISA was more cost-effective than EIA should be used to supplement PT for a more complete diagnosis of allergy.     

IgE on Langerhans cells in the skin of patients with atopic dermatitis and birch allergy

Epidermal cell suspensions from the skin of seven patients with atopic dermatitis (AD) and seven healthy non-atopic controls were investigated for the presence of surface HLA-DR and CD1 antigen, and IgE using indirect and double-staining immunofluorescence techniques. Fifty-seven percent of all CDI + and 68% of all HLA-DR + cells from the patients demonstrated IgE on their surface, indicating that Langerhans cells (Lc) in AD may be a heterogeneous population with regard to surface characteristics. No IgE + cells were found in the epidermal cell suspensions from the healthy non-atopic controls. An attempt lo demonstrate birch pollen antigen on the surface of Lc from the same patients all strongly allergic to birch pollen, using indirect immunofluorescence techniques, was unsuccessful, also after in vitro incubation of the Lc with high concentration of the birch antigen.