Allergy to miscellaneous household arthropods

Of the various arthropods, humans have the greatest contact with mites and cockroaches, and as a result, allergies to these two groups have been the most frequently reported. Changes in lifestyle and living environment have encouraged the growth of arthropods other than mites and cockroaches, and consequently, human exposure to antigens derived from the new arthropods has increased. Although systematic approaches to and immunobiochemical studies of these arthropods are relatively sparse compared with those of mites and cockroaches, recent reports have shown that many species of household arthropods can elicit IgE-mediated reactions via inhalation, biting, or stinging. In this chapter, we review the other arthropods that can induce allergic reaction to human beings. Where the information exists, the frequency of sensitivity and clinical manifestation, and the characterization of the allergens are also reviewed. Virtually all species of arthropods may be sources of allergens that can sensitize and induce IgE-mediated allergic reactions in humans.     

Clinical significance of dust mite allergens

Dust mites are an important cause of allergic diseases worldwide. The traces of Dermatophagoides farinae and Dermatophagoides pteronyssinus can be found all over the world, while Blomia tropicalis are more common allergenic mites in tropical areas. A variety of allergenic components in dust mites have been found, apart from the different positive rates of IgE reactions in dust mite allergic patients, their biological characteristics, effects on the innate immune system, and especially their distribution characteristics in patients are different. Studying the relationship between dust mite allergens and clinical significance will help for diagnosis of patients and formulation of corresponding Allergen Specific Immunotherapy.

     

Structural biology of mite allergens

Mite allergens contribute to a significant proportion of human allergic symptoms, including asthma and rhinitis. The development of therapies to treat and prevent these symptoms depends largely on our understanding of the properties of these allergens. Much effort has been devoted to determining the structure and organization of mite allergens, particularly of the house dust mites, toward understanding their activities and how they elicit immunological responses in humans. Here, we review the structural biology of the major allergens from two species of house dust mites, Dermatophagoides farinae and D. pteronyssinus, as well as allergens from a storage mite, Blomia tropicalis. The knowledge gained from the structural biology of these allergens will enable progress in producing novel, more effective treatments for mite allergies based on specific immunotherapy approaches.     

The colonisation of new houses by house dust mites (Acari: Pyroglyphidae)

House dust mites,Dermatophagoides species (Acari: Pyroglyphidae), produce allergens, known for the provocation of asthma and other allergic reactions. To determine the time needed for complete colonisation of a new house by house dust mites, dust samples were collected from carpets of houses varying from 2 weeks to 2 years in age. In contrast to the expectation, no relation was found between age of the houses on the one hand and average levels of mite-allergensDer pI andDer pII and mite numbers on the other. However, presence of dogs appeared to be positively related to allergen levels. Furthermore, carpets in bedrooms appeared to contain more allergens than carpets in living-rooms. Finally, the age of the mattress was not related to allergen levels of bedroom floors.     

盐城地区未成年过敏性疾病患者吸入性过敏原IgE检测结果分析

摘要 目的：通过研究分析盐城地区未成年过敏性疾病患者吸入性过敏原特异性IgE检测结果分布变化特点,为过敏性疾病预防和临床诊疗提供科学依据。方法：自2020年1月至2021年3月期间,选择430例未成年(<18岁)过敏性疾病患者,血清检测方法采用欧蒙公司生产的过敏原特异性IgE检测试剂盒。结果：430例患者中,血清过敏原IgE阳性166例(38.60%),其中尘螨和屋尘是主要的吸入性过敏原。血清IgE阳性率男性39%,女性36% (P>0.05),中学组女性阳性率（61.11 %）高于男性（45.83 %）（P<0.05）。不同年龄组间IgE阳性率有统计学差异（P<0.05）,蟑螂、尘螨、霉菌、豚草、屋尘和年龄组间有统计学差异（P<0.05）。不同临床症状与IgE阳性率有统计学差异(P<0.05),其中呼吸道过敏症状组IgE阳性率最高（48.30 %）,不同症状组间主要过敏原都是尘螨。屋尘阳性患者均合并尘螨阳性,其中70.93 %的患者表现出了呼吸道过敏症状。结论：尘螨、屋尘是盐城地区未成年过敏性疾病患者最主要的吸入性过敏原,研究血清过敏原分布,对未成年人过敏性疾病的预防、诊疗具有重要意义。     

A review of recent immunochemical studies ofBlomia tropicalis andEuroglyphus maynei allergens

Exposure to mites other thanDermatophagoides spp., particularlyBlomia tropicalis andEuroglyphus maynei, has been increasingly recognized as a cause of asthma. Positive skin tests and serum IgE antibodies toB. tropicalis have been reported in asthmatic patients from several areas of the world, including São Paulo (Brazil), Hong Kong and Tampa (Florida, USA). Analysis ofB. tropicalis extracts showed undetectable levels of the major Group I and Group IIDermatophagoides spp. allergens. Immunoabsorption experiments showed that most of the IgE antibodies toB. tropicalis ( 70%) reacted with species-specific allergens. Murine monoclonal antibodies toB. tropicalis could present antigens that were recognized by human IgG antibodies. Sensitization toE. maynei has been reported in Europe, North and South America and Australia. Analysis of four differentE. maynei extracts by ELISA and RIA showed thatE. maynei produces an allergen that is antigenically related toDermatophagoides Group I allergens. The amino acid sequence of this allergen (Eur m I) has recently been reported. Further identification and purification ofB. tropicalis andE. maynei allergens is required to develop specific assays for measuring these allergens in dust samples. This will make it possible to investigate the relationship between exposure toB. tropicalis orE. maynei and the development of sensitization and allergic disease.     

Population growth and allergen accumulation of <Emphasis Type="Italic">Dermatophagoides pteronyssinus</Emphasis> cultured at 20 and 25°C

The house dust mites, Dermatophagoides pteronyssinus and D. farinae are cultured commercially and in research laboratories and material is harvested from these cultures to make extracts that are used for diagnosis, immunotherapy and research. Temperature and other climatic conditions can influence population growth rates, dynamics of allergen production, and the associated endotoxin, enzyme and protein levels of the mite material harvested from these cultures. Here we determined how temperature affected these parameters. Dermatophagoides pteronyssinus was cultured at 20 and 25°C at 75% relative humidity, and at 2-week intervals the concentrations of mites, Der p 1 and Der p 2 allergens, endotoxin, and selected enzymes were determined. Mite density increased exponentially but growth rate and final population density were greater at 25°C compared to 20°C. The combined allergen (Der p 1 + Der p 2) concentrations accumulated in the cultures at about the same rate at both temperatures. However, individual Der p 1 and Der p 2 accumulation rates varied independently at the two temperatures. Der p 1 accumulated faster at 20°C whereas Der p 2 accumulated faster at 25°C. The amount of Der p 1 in whole cultures was greater than the amount of Der p 2. The concentration of allergen for washed mites harvested from the cultures was much less than for the whole cultures. Our study demonstrated that temperature is an important factor in population growth and the dynamics of allergen production in cultured mites.     

义乌地区儿童过敏性结膜炎过敏原分析

目的了解过敏性结膜炎患儿常见过敏原及其分布特征,为预防和脱敏治疗提供依据。方法采用免疫印迹法对363例过敏性结膜炎患儿进行血清过敏原检测,并对结果进行分组比较。结果患儿中检出率居前3位的吸入性过敏原分别为尘螨(50.41%)、猫毛(3.03%)和霉菌(2.48%);检出率居前3位的食物性过敏原分别为淡水鱼(10.74%)、海鱼(7.44%)和鸡蛋白(6.34%)。吸入性过敏原(62.26%)和食物性过敏原(41.60%)总检出率比较差异有统计学意义(P0.05)。婴幼儿组、学龄前组和学龄组患儿均以尘螨为常见过敏原,其检出率分别为33.33%、52.76%和52.00%。不同年龄患儿牛奶过敏检出率比较差异有统计学意义(P0.05),婴幼儿组牛奶过敏检出率最高,为12.82%。男、女患儿过敏原阳性率比较差异无统计学意义(P0.05)。不同年龄患儿过敏原阳性率比较差异无统计学意义(P0.05)。婴幼儿组、学龄前组和学龄组患儿均以单纯吸入性过敏原和单一过敏原为常见。1月-3月为儿童过敏性结膜炎的低发季节。结论通过血清过敏原检测可明确过敏性结膜炎的过敏原。尘螨是本地区儿童过敏性结膜炎常见过敏原。     

Evaluation of the age of onset of respiratory allergic symptomatology

Summary In order to evaluate the age of ouset of respiratory allergic symptoms we examined 2315 patients (656 children and 1659 adults) coming to our clinic as out patients. Each patient underwent the following diagnostic tests: anamnestic and clinical examination, skin-tests for the most common allergens and, when requested, Radioallergosorbent test (RAST) and specific and non specific BPT.We selected 278 children and 673 adults for whom it was possible to establish (on the basis of precise anamnestic considerations) the age at which the respiratory symptoms first appeared.Among these, 300 reacted only toParietaria pollen, 58 only to grass pollen, 420 only to house-dust mite, and 173 were not allergic.Patients reacting to multiple allergens were excluded from the analysis.The results of our study show a significant precocity of the onset of symptoms related to allergic sensitization to mites with peak level at 5 years.On the other hand, the onset of pollen-related symptoms was later on (peak level at 20–25 years forParietaria pollen and 30–35 years for grass pollen). For non allergic patients we did not find a definite age of onset.     

Clinical significance of allergic sensitization toOlea europaea L. pollen in Naples area,Italy

Summary The aim of this study is the evaluation of clinical significance of the allergic sensitization toOlea europaea L. pollen allergens in the Naples area, because in the last 10 years an increasing frequency of IgE mediated sensitization to these allergens has been observed. 4124 patients of both sexes (2989 adults and 1153 children) consecutively examined in our Allergological Center from January 1, 1988 to December 30, 1989 have been considered in this study. The patients were selected on the basis of a history of rhinitis (R) and/or asthma (A) and were evaluated by clinical examination, SPT, RAST and specific or aspecific BPT. Among 2267 adults and 879 children sensitized to almost one aeroallergen we found respectively 306 (13.49%) and 75 (8.53%) subjects with an allergic sensitization toOlea europaea L. pollen. The frequency of clinical manifestation was respectively R+A (58.16%), R (39.54%), A (2.28%) in adults; R+A (61.33%), R (26.66%), A (12%) in children. A monosensitization toOlea europaea L. pollen was found in 1.33% of children and in 2.28% of adults examined. The association with other allergens especially with mites and/or other pollen was very common.     

Cross-reactivity between storage and dust mites and between mites and shrimp

Many patients have sensitivities to multiple species of storage and house dust mites. It is not clear if this is because patients have multiple sensitivities to species-specific mite allergens or if these mites share many cross-reacting allergens. Our objective was to further define the cross-allergenicity between several species of storage and house dust mites using crossed-immunoelectrophoresis (CIE), crossed-radioimmunoelectrophoresis (CRIE), immunoblotting, and ELISA. CIE and CRIE reactions revealed that storage mites shared two cross-antigenic molecules and one of these bound IgE in a serum pool from mite allergic patients. Antibody in anti-sera built to each species of mite recognized many SDS–PAGE resolved proteins of other mite species and this suggested the potential for other cross-reactive allergens. Among patient sera, IgE bound to many different proteins but few had IgE that bound to a protein with common molecular weights across the mite species and this suggested mostly species-specific allergens. Antiserum built to each mite species precipitated one protein in shrimp extracts that bound anti-Der p 10 (tropomyosin) and IgE in the serum pool. Anti-Der p 10 showed strong binding to shrimp tropomyosin but very little to any of the mite proteins. ELISA showed the mite extracts contained very little tropomyosin. The storage and dust mites investigated contain mostly species-specific allergens and very small amounts of the pan-allergen tropomyosin compared to shrimp and snail.     

Modelling and Bioinformatics Analysis of the Dimeric Structure of House Dust Mite Allergens from Families 5 and 21: Der f 5 Could Dimerize as Der p 5

Abstract

Allergy represents an increasing thread to public health in both developed and emerging countries and the dust mites Dermatophagoides pteronyssinus (Der p), Blomia tropicalis (Blo t), Dermatophagoides farinae (Der f), Lepidoglyphus destructor (Lep d) and Suidasia medanensis (Sui m) strongly contribute to this problem. Their allergens are classified in several families among which families 5 and 21 which are the subject of this work. Indeed, their biological function as well as the mechanism or epitopes by which they are contributing to the allergic response remain unknown and their tridimensional structures have not been resolved experimentally except for Blo t 5 and Der p 5. Blo t 5 is a monomeric three helical bundle, whereas Der p 5 shows a three helical bundle with a kinked N-terminal helix that assembles in an entangled dimeric structure with a large hydrophobic cavity. This cavity could be involved in the binding of hydrophobic ligands, which in turn could be responsible for the shift of the immune response from tolerance to allergic inflammation. We used molecular modelling approaches to bring out if other house dust mite allergens of families 5 and 21 (Der f 5, Sui m 5, Lep d 5, Der p 21 and Der f 21) could dimerize and form a large cavity in the same way as Der p 5. Monomeric models were first performed with MODELLER using the experimental structures of Der p 5 and Blo t 5 as templates. The ClusPro server processed the selected monomers in order to assess their capacity to form dimeric structures with a positive result for Der p 5 and Der f 5 only. The other allergens (Blo t 5, Sui m 5, Lep d 5, Der p 21 and Der f 21) did not present such a propensity. Moreover, we identified mutations that should destabilize and/or prevent the formation of the Der p 5 dimeric structure. The production of these mutated proteins could help us to understand the role of the dimerization process in the allergic response induced by Der p 5, and if Der p 5 and Der f 5 behave similarly.     

Storage mites

The interest in allergy to storage mites has increased over the past few years. Storage mites feed on a variety of substances and they can be found in many different products such as grain, flour, hay and straw, but also in house dust samples. The more common genera areLepidoglyphus, Tyrophagus, Glycyphagus, Acarus andBlomia. Several species of storage mites have been shown to cause IgE-mediated sensitization among rural workers, who to a varying extent develop asthma, rhinitis or conjunctivitis when exposed to barn dust. However, a number of studies, have reported on sensitization to storage mites also among urban people, indicating that sensitization is not restricted to individuals with occupational exposure. Regarding the allergenic relationship between storage mites and house dust mites, there appears to be a limited allergenic cross-reactivity between the two species. However, both species also possess their own unique allergens. Further research on identification and characterization of storage mite allergens and their cross-reactivity is required to understand the complexity of epitopes and allergens.     

House-dust mite sensitivity among rural and urban asthmatics of West Bengal, India: a comparison

House-dust mite allergy is a fairly common problem in West Bengal among individuals sensitive to dust inhalation. House-dust mites belonging to the genusDermatophagoides are abundant in the homes of asthmatic patients residing in urban as well as rural areas of West Bengal. The frequency of positive skin reaction to different dust-related allergens tested was higher (χ²=5.4777, df = 1;P < 0.05) among patients of urban areas compared with that among the patients of rural areas. Urban patients showed more frequent skin reaction towards cockroach allergen, while rural patients are more sensitive to hay-dust allergen and these are very much related to their local environmental conditions. Analysis of radioallergosorbent test (RAST) results against house dust (HD) and mites reveal that 73 and 90% patients of both urban and rural areas responded positively towardsDermatophagoides pteronyssinus (DP) andDermatophagoides farinae (DF) antigens, respectively. The present study indicates no significant difference in house-dust mite sensitivity and mite levels in homes among the rural and urban asthmatics of West Bengal, India as evidenced from the results of analysis of dust samples, allergy skin test and detection of mite-specific IgE antibodies by RAST.     

The role of the sensitization to storage mites in the diagnosis of allergic respiratory diseases

Summary Numerous studies suggest the capacity of storage mites (S.M.) to induce IgE-mediated reactions but their etiopathogenetic role in allergic respiratory diseases has not yet been established. Therefore we examined 283 patients affected by rhinitis and/or bronchial asthma resident in urban and rural areas who underwent skin tests and a RAST with a group of allergens including S.M. (Acarus s., Lepidoglyphus d., Glycyphagus d., Tyrophagus p.).The incidence of patients showing a positive reaction to S.M. was evaluated according to their place of residence and work. 48 patients were selected who resulted positive to mites; 28 of them resulted positive to S.M. and pyroglyphid and 5 to S.M. only.The relationship between skin tests and RAST for S.M. positive patients resulted high forL.d. (70%),G.d. (75%),T.p. (80%) and low forA.s. (58%). In RAST positive subjects cross-reactivity withD. ptero was evaluated:A.s. (70%),L.d. (80%),T.p. (75.4%),G.d. (78.9%).Dwelling and place of work of skin and RAST positive patients revealed an equal distribution between urban and rural populations for S.M.; however, while in urban areas the association with pyroglyphid mites is constant, the rare single sensitivities are found only in rural areas and in farmers. From our data it emerges that the allergological diagnostics must use S.M. when considering respiratory diseases of professionally exposed subjects and residents of given areas. An interpretation of their etiologic role, given the frequent association with pyroglyphid mites, will demand further diagnostic data and an identification and purification of the clinically relevant allergens.     

Effect of certain socio-ecological factors on the population density of house dust mites in mattress-dust of asthmatic patients of Calcutta, India

Allergy to house dust mites, particularly tothe genus Dermatophagoides is a fairlycommon problem in Calcutta and its adjoiningareas since last two decades. Both the commonspecies of the genus Dermatophagoidesi.e. D. farinae and D.pteronyssinus are found to be abundant in thedust samples collected from beds of patientssuffering from nasobronchial allergic disordes.The presence of these mites in quite a goodnumber in the patients' beds are clinicallycorrelated with the aetiopathology of variousallergic manifestations like bronchial asthma.Dermatophagoides mites may occupydifferent niches in the homes of asthmatics andare more common in beds than elsewhere in thehouse, however, the distribution and abundanceof these mites are influenced by somesocio-ecological factors. The aim and objectiveof the present study is to assess the impact ofsome common socio-ecological managementpractices like the age of house, age ofmattress, type of mattress, frequency ofcleaning of the mattress and even the economicstatus of the patients on the growth,multiplication and finally accumulation ofthese mites in the patients' surroundings.Proper identification of offending allergensand subsequent reduction of load of these miteallergens from the patient's environment may behelpful for the prophylactic management ofthese diseases in Calcutta metropolis.     

Molecular identification of house dust mites and storage mites

Mites are known causes of allergic diseases. Currently, identification of mites based on morphology is difficult if only one mite is isolated from a (dust) sample, or when only one gender is found, or when the specimen is not intact especially with the loss of the legs. The purpose of this study was to use polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) of the ITS2 gene, to complement the morphological data for the identification of mites to the species level. For this, six species were cultured: Dermatophagoides pteronyssinus, D. farinae, Blomia tropicalis, Tyrophagus putrescentiae, Aleuroglyphus ovatus and Glycycometus malaysiensis. Genomic DNA of the mites was extracted, quantified, amplified and digested individually with restriction enzymes. Hinf I and Ple I differentiated the restriction patterns of D. pteronyssinus and D. farinae. Bfa I and Alu I enzymes differentiated B. tropicalis and G. malaysiensis. Ple I enzyme was useful for the differentiation between T. putrescentiae and A. ovatus. Bfa I was useful for the differentiation of G. malaysiensis from the rest of the species. In conclusion, different species of mites can be differentiated using PCR–RFLP of ITS2 region. With the established PCR–RFLP method in this study, identification of these mites to the species level is possible even if complete and intact adult specimens of both sexes are not available. As no study to date has reported PCR–RFLP method for the identification of domestic mites, the established method should be validated for the identification of other species of mites that were not included in this study.     

Domestic arthropods and their allergens

Allergy prevalence has increased worldwide over the last 25 years along with industrialization and westernized lifestyles. Indoor allergens are primarily responsible for the sensitization and development of atopic diseases. The main indoor allergens are known to be derived from various arthropods which account for up to 80% of the kingdom Animalia. The two classes of arthropods are Insecta, which includes cockroaches, flies, mosquitoes, ants and silverfishes, and Arachnida, which includes mites, spiders, ticks, and scorpions and are the main sources of the allergens. Excreted materials, cast-overs from skin-molting, and dead debris are sources of allergens that can sensitize genetically predisposed individuals and elicit allergic disorders. The use of molecular biology techniques has contributed to the identification and characterization of an ever-increasing number of allergens. However, key determinants and allergen properties that drive allergic responses are poorly understood. The biological characterization of allergens will provide an understanding of the pathogenesis of allergic diseases and contribute to the development of new diagnostic and therapeutic approaches.     

Delayed hypersensitivity to house dust-storage mites Thyrophagus putrescentiae in experimental allergic dermatoses]

House dust mites and storage mites proved to be one of the main allergens causing hypersensitivity in atopic dermatitis in allergic patients. The authors reproduced experimental allergic dermatosis on the model of delayed type hypersensitivity in guinea pigs, caused by sensitization to the allergen from the mite's bodies Tyrophagus putrescentiae--species having wide distribution in the country. The results characteristic for T-cell type hypersensitivity have been obtained: delayed positive skin tests after 24 hours, typical histomorphological picture (strong allergic alteration, epidermis desquamation, vasculitis, dermis T-cell infiltration and spongiosis--Waksman's syndrome). It is concluded that side by side with humoral IgE-mediated reaction there is strong delayed T-cell hypersensitivity to the storage mites Tyrophagus putrescentiae.     

Transgenic ryegrasses (Lolium spp.) with down-regulation of main pollen allergens

Ryegrass pollen (Lolium species) is a widespread source of air-borne allergens and is a major cause of hayfever and seasonal allergic asthma, which affect approximately 25% of the population in cool temperate climates. The main allergens of ryegrass pollen are the proteins Lol p 1 and Lol p 2. These proteins belong to two major classes of grass pollen allergens to which over 90% of pollen-allergic patients are sensitive. The functional role in planta of these pollen allergen proteins remains largely unknown. Here we describe the generation and analysis of transgenic plants with reduced levels of the main ryegrass pollen allergens, Lol p 1 and Lol p 2 in the most important worldwide cultivated ryegrass species, L. perenne and L. multiflorum. These transgenic plants will allow the study of the functional role in planta of these pollen proteins and the determination of potential for development of hypo-allergenic ryegrass cultivars.