Identification of polcalcin as a novel allergen of Amaranthus retroflexus pollen

IntroductionAmaranthus retroflexus (Redroot Pigweed) is one of the main sources of allergenic pollens in temperate areas. Polcalcin is a well-known panallergen involved in cross-reactivity between different plants. The aim of this study was the molecular cloning and expression of polcalcin, as well as evaluating its IgE-reactivity with A. retroflexus sensitive patients’ sera.MethodsAllergenic extract was prepared from A. retroflexus pollen and the IgE-reactivity profile was determined by ELISA and immunoblotting using sera from twenty A. retroflexus sensitive patients. Polcalcin-coding sequence was amplified by conventional PCR method and the product was inserted into pET-21b(+) vector. The recombinant protein was expressed in E. coli BL21 and purified by metal affinity chromatography. The IgE-binding capability of the recombinant protein was analyzed by ELISA and immunoblotting assays, and compared with crude extract.ResultsOf 20 skin prick test positive patients, 17 patients were positive in IgE-specific ELISA. Western blotting confirmed that approximately 53% of ELISA positive patients reacted with 10 kDa protein in crude extract. The A. retroflexus polcalcin gene, encoding to 80 amino acid residues was cloned and expressed as a soluble protein and designated as Ama r 3. The recombinant polcalcin showed rather identical IgE-reactivity in ELISA and western blotting with 10 kDa protein in crude extract. These results were confirmed by inhibition methods, too.ConclusionThe recombinant form of A. retroflexus polcalcin (Ama r 3) could be easily produced in E. coli in a soluble form and shows rather similar IgE-reactivity with its natural counterpart.     

Allergen avoidance in the secondary and tertiary prevention of allergic diseases: does it work?

Although allergen avoidance is widely recommended as part of a secondary and tertiary prevention strategy for allergic diseases, a clear-cut demonstration of its effectiveness is still lacking. Ongoing observational secondary prevention cohorts show that sensitisation to mite can be prevented in the short term by allergen avoidance measures, but further follow-up of these children is needed to show if this effect can be sustained, as well as to ascertain its impact on allergic disease. More well-designed trials are still required before we can give any conclusive advice to our patients. Considering the management of allergy, current evidence suggests that interventions in children (either single or multifaceted) may be associated with some beneficial effect on asthma control, but no conclusive evidence exists regarding rhinitis or eczema. Conversely, there is little evidence to support the recommendation of allergen avoidance methods in adults with asthma and rhinitis. There is a need for an adequately designed trial assessing the effects of a multifaceted intervention in this age group.     

Immunotherapy in the age of anti-IgE

Recent results of allergen immunotherapy research have continued to validate efficacy and have also demonstrated a truly preventive aspect for this treatment. This review summarizes the basic principles of effective allergen immunotherapy and highlights some of the advances that have been published in the past year. These studies show that allergen immunotherapy, when done appropriately and properly, not only causes a decrease in symptoms and use of medication as well as an improved quality of life, but that the progression of disease from allergic rhinitis to asthma is substantially decreased and the development of new allergies is diminished. In addition, laboratory studies continue to demonstrate significant changes in the immune system with a shift in the immune pathway from TH₂ toward a TH₁ response. The impact of anti-IgE as a therapeutic agent with allergen immunotherapy is also be reviewed.     

新鲜羊膜致I型超敏反应的变应原性研究

研究新鲜人羊膜的变应原性及其致敏后发生I型超敏反应的可能性。建立豚鼠全身主动过敏实验模型。分新鲜羊膜组、新鲜蛋清组(阳性对照)和PBS液组(阴性对照),每组10只豚鼠。观察豚鼠在致敏期和激发后的反应,采用化学荧光法检测外周血组胺含量,血液流变分析系统检测4项血液流变学指标(全血高切变率黏度、全血低切变率黏度、血浆黏度、红细胞聚集指数)。致敏期间各组豚鼠的体重变化无明显差别(P>0.05);激发后羊膜组豚鼠与阴性组表现一致,无异常反应;羊膜组外周血组胺含量及4项血液流变学指标均与阴性对照无明显差别(P>0.05),与阳性对照有显著性差异(P<0.01)。经规范化无菌处理后的新鲜羊膜,一般不具有变应原性,不会引起I型超敏反应。     

Screening 34 Peanut Introductions for Allergen Content Using ELISA

Peanut is one of the most allergenic foods and reports of accidental ingestion of peanuts in unsuspected food are increasing. No information is available on the allergen content of peanut germplasm grown commercially and used in the food and confectionery industry. The objectives of this study were: (1) to determine the allergen contents of 34 peanut introductions (PI); and (2) to identify naturally occurring allergen-free and/or low or hypoallergenic peanuts germplasm. A basic ELISA protocol was utilized to detect the presence of antigens in the peanut lines using a pool of human sera from patients with documented history of peanut allergy. Two naturally occurring low, or hypo-allergenic germplasm were identified as PI 261942 and PI 338386. Both are Valencia market types with total allergen content significantly lower (P ≤0.05) than that of PI 119880 (0.550), PI 119876 (0.415) and PI 118991 (0.410) three Valencia market types and PI 262111 (0.485), a Virginia market type. No allergen-free PI was found. Allergen content of peanut lines from Bolivia and Paraguay were significantly (P ≤0.05) different to those from Venezuela. No significant difference was observed in the allergen content of the four market types.     

Allergen extracts directly mobilize and activate human eosinophils

Allergic diseases are characterized by the presence of eosinophils, which are recruited to the affected tissues by chemoattractants produced by T cells, mast cells and epithelium. Our objective was to evaluate if allergens can directly activate human eosinophils. The capacity of purified allergen extracts to elicit eosinophil chemotaxis, respiratory burst, degranulation and up-regulation of the adhesion molecule complement receptor 3 (CR3) was determined in eosinophils isolated from healthy blood donors. Eosinophils stimulated with an extract from house dust mite (HDM) released the granule protein major basic protein (MBP) and up-regulated the surface expression of CR3. Cat allergen extracts also induced the up-regulation of CR3, but not the release of MBP; instead cat, as well as birch and grass allergens, elicited the release of eosinophil peroxidase (EPO). In addition, grass pollen extract caused the secretion of MBP. None of the allergens stimulated eosinophilic cationic protein release, nor production of free oxygen radicals. Both HDM and birch extracts were chemotactic for eosinophils. These findings establish that common aeroallergens can directly activate eosinophils in vitro. We propose that eosinophil activation in vivo is not exclusively mediated by cytokines and chemokines of the allergic inflammatory reaction, but could partly be the result of direct interaction between allergens and eosinophils.     

84例变应性鼻炎患儿过敏原皮内试验结果分析

目的 了解新疆地区变应性鼻炎患儿气传过敏原的分布状况,探讨气传变应原分布的地区差异及产生原因,为本地区儿童变应性鼻炎的防治方案提供客观依据.方法 采用阿罗格(NHD)点刺液进行皮肤点刺试验84例变应性鼻炎患儿进行气传变应原测试.结果 84例变应性鼻炎患儿吸入变应原测试总阳性率96.4%(81例),以藜属花粉最高70.2%(59例),蒿属植物次之42.9%(36例),其后依次为杨树27.4%(23例),榆树25.0%(21例),槭树17.8%(15例),柳树11.9%(10例),豚草(巨大豚草、普通豚草)11.9%(10例),粉螨10.7%(9例),尘螨9.5%(8例),交链孢霉8.3%(7例),特异青霉7.1%(6例),白色念珠菌4.8%(4例)等.81例对不同变应原过敏,其中42例(51.9%)患儿对2种或2种以上变应原过敏.点刺试验皮肤反应强度蒿属最明显,强阳性占蒿属过敏病人的50.0%,藜属次之,强阳性占藜属过敏病人的40.7%.结论 藜属和蒿属为新疆地区变应性鼻炎患儿最主要的变应原,在治疗过程中对这类变应性鼻炎患儿可采取有效的避、忌、替、移等措施,明确变应原后对特异性免疫治疗具有重要的指导意义.     

非特殊类型湿疹临床相关因素分析

目的分析非特殊类型湿疹的临床特征及引起该病的临床相关因素,为早期预防、诊治及预后提供参考依据。方法对我院收治的54例非特殊类型湿疹患者的临床病例资料进行回顾性统计、分析。结果非特殊类型湿疹患者,夏天发病的占总数的51.9%（28/54）,秋季次之,约占总数的27.8%（15/54）;在发病部位上面,皮疹首发部位以四肢最多见,占总数的51.9%（28/54）;其次为躯干,约占总数的24.1%（13/54）。不同年龄组非特殊类型湿疹患者在发病年龄、发病性别及发病季节分布上差异无统计学意义（P〉0.05）。结论非特殊类型湿疹是由外界刺激与内在身体因素共同导致的,可发生于任何年龄段人群的任何部位,为防止进一步加重,应对其致病源进行及时发现和处理。