Title: Indoor allergens and asthma:Report of the Third International Workshop
Abstract: In parallel with changes in lifestyle over the last 50 years (sedentary living in warm houses with extensive furnishing and low ventilation rates), there has been a progressive increase in the prevalence and morbidity of asthma in many parts of the world. The increase has been in perennial rather than seasonal asthma, and a large proportion of the patients are sensitized to one or more of the allergens found predominantly inside houses, that is, indoor allergens. The Third International Workshop on Indoor Allergens and Asthma was designed to discuss recent progress in basic and clinical research in this area, to formulate recommendations for allergen-specific management of asthma, and to consider future research directions. As with the two previous workshops, discussion topics included biology; allergen immunochemistry; molecular biology and immune response; epidemiology of asthma; and the role of allergen avoidance.1Platts-Mills TAE De Weck A. Dust mite allergens and asthma—a world wide problem.Bull WHO. 1989; 66: 769-780Google Scholar, 2Platts-Mills TAE Thomas WR Aalberse RC Vervloet D Chapman MD et al.Dust mite allergens and asthma: report of a second international workshop.J Allergy Clin Immunol. 1992; 89 (Co-chairmen): 1046-1060Abstract Full Text PDF PubMed Scopus (424) Google Scholar Because of dramatic progress in recent years, the Third International Workshop was expanded to cover not only house dust mite allergens but also allergens from cat, dog, and cockroach, for which immunochemical and epidemiologic data are available.Over the past 5 years there have been significant advances in several areas of research on indoor allergens, including: (1) cloning and expression of recombinant allergens,3Scheiner O Kraft D. Basic and practiced aspects of recombinant allergens.Allergy. 1995; 50: 384-391Crossref PubMed Google Scholar, 4Stewart GA Thompson PJ. The biochemistry of common aeroallergens.Clin Exp Allergy. 1995; 25: 1020-1044Google Scholar, 5Chapman MD. Allergens. In: Delves PJ, Roitt IM, editors. Encyclopedia of immunology. 2nd ed. London: Academic Press; In press.Google Scholar, 6Platts-Mills TAE. Allergens.in: 5th ed. Samter's immunologic diseases.vol II. Little, Brown & Company, Boston1994: 1231-1256Google Scholar, 7Thomas WR. Molecular analysis of house dust mite allergens. In: Walker MR, Roberts AM, editors. Molecular analysis of mediated hypersensitivity and strategies for immunologic intervention. Chichester, UK: Wiley & Sons; In press.Google Scholar (2) analysis of T-cell responses to indoor allergens, derivation of T-cell clones, and analysis of T-cell epitope specificity and cytokine profiles,8Kapsenberg ML Wierrenga EA Bos JD Jansen HM. Functional subsets of allergen reactive human CD4+ T cells.Immunol Today. 1991; 12: 392-395Abstract Full Text PDF PubMed Google Scholar, 9Van Neerven RJ Ebner C Yssel H Kapsenburg ML Lamb JR. T cell responses to allergens: epitope-specificity and clinical relevance.Immunol Today. 1996; 17: 526-532Abstract Full Text PDF PubMed Google Scholar (3) investigation of the dose-response relationship between exposure to mite, cat, and cockroach allergens and sensitization,10Kueher J Frischer J Meiner R et al.Mite exposure is a risk factor for the incidence of specific sensitization.J Allergy Clin Immunol. 1994; 94: 44-52Abstract Full Text Full Text PDF PubMed Scopus (176) Google Scholar, 11Sporik R Ingram JM Price W Sussman JH Honsinger RW Platts-Mills TAE. Association of asthma with serum IgE and skin-test reactivity to allergens among children living at high altitude: tickling the dragon's breath.Am J Respir Crit Care Med. 1995; 151: 1388-1392Crossref PubMed Google Scholar, 12Call RS Smith TF Morris E Chapman MD Platts-Mills TAE. Risk factors for asthma in inner city children.J Pediatr. 1992; 121: 862-866Abstract Full Text PDF PubMed Google Scholar, 13Custovic A Taggart SCO Francis HC Chapman MD Woodcock A. Exposure to house dust mite allergens and the clinical activity of asthma.J Allergy Clin Immunol. 1996; 98: 64-72Abstract Full Text Full Text PDF PubMed Google Scholar and (4) epidemiologic studies on indoor allergens as risk factors for the symptoms of asthma and bronchial hyperreactivity (BHR).14Wickman M Nordvall SL Pershagen G Sundell J Schwartz B. House dust mite sensitization in children and residential characteristics in a temperate region.J Allergy Clin Immunol. 1991; 88: 89-95Abstract Full Text PDF PubMed Google Scholar, 15Munir AKM Bjorksten B Einarsson R Schou C Ekstrand-Tobin A Warner A et al.Cat (Fel d I), dog (Can f I) and cockroach allergens in homes of asthmatic children from three climatic zones in Sweden.Allergy. 1994; 49: 508-516Crossref PubMed Google Scholar, 16Peat JK Tovey E Gray EJ Mellis CM Woolcock AJ. Asthma severity and morbidity in a population sample of Sydney schoolchildren, II: importance of house dust mite allergen.Aust N Z J Med. 1994; 24: 270-276Crossref PubMed Google Scholar, 17Rosenstreich DL Eggleston P Kattan M et al.Cockroaches in the asthma morbidity of inner-city children.N Engl J Med. 1997; 336: 1356-1363Crossref PubMed Scopus (821) Google ScholarBetter definition of the allergens has made it possible to analyze their structure and biologic function and to define epitopes recognized by antibodies or T cells. Information obtained from those studies has provided exciting possibilities for developing new vaccines for safe and effective immunotherapy.9Van Neerven RJ Ebner C Yssel H Kapsenburg ML Lamb JR. T cell responses to allergens: epitope-specificity and clinical relevance.Immunol Today. 1996; 17: 526-532Abstract Full Text PDF PubMed Google Scholar, 18Norman PS Ohman JL Long AA Creticos PS Gefter MA Shaked Z et al.Treatment of cat allergy with T cell reactive peptides.Am J Respir Crit Care Med. 1996; 154: 1623-1628Crossref PubMed Google Scholar, 19Smith AM Chapman MD. Reduction in IgE binding to allergen variants generated by site-directed mutagenesis: contribution of disulfide bonds to the antigenic structure of the major house dust mite allergen, Der p 2.Mol Immunol. 1996; 33: 399-405Crossref PubMed Scopus (136) Google Scholar Studies of T-cell responses to dust mites have confirmed the dominance of T-helper cell (TH2) responses in allergic individuals. Influencing the development of these TH2 responses in early childhood or modifying these responses in allergic individuals should be the objective of future research on immunotherapy for asthma.20Holt PG. A potential vaccine strategy for asthma and allied atopic diseases during early childhood.Lancet. 1994; 344: 456-458Abstract PubMed Scopus (127) Google ScholarEvidence for a dose-response relationship between exposure and sensitization has been refined for both mite and other allergens. Studies in Australia, France, Germany, Japan, and the United States have confirmed that the pattern of sensitization to specific allergens reflects the mean level of allergen found in houses in the communities where the patients live.11Sporik R Ingram JM Price W Sussman JH Honsinger RW Platts-Mills TAE. Association of asthma with serum IgE and skin-test reactivity to allergens among children living at high altitude: tickling the dragon's breath.Am J Respir Crit Care Med. 1995; 151: 1388-1392Crossref PubMed Google Scholar, 12Call RS Smith TF Morris E Chapman MD Platts-Mills TAE. Risk factors for asthma in inner city children.J Pediatr. 1992; 121: 862-866Abstract Full Text PDF PubMed Google Scholar, 14Wickman M Nordvall SL Pershagen G Sundell J Schwartz B. House dust mite sensitization in children and residential characteristics in a temperate region.J Allergy Clin Immunol. 1991; 88: 89-95Abstract Full Text PDF PubMed Google Scholar, 16Peat JK Tovey E Gray EJ Mellis CM Woolcock AJ. Asthma severity and morbidity in a population sample of Sydney schoolchildren, II: importance of house dust mite allergen.Aust N Z J Med. 1994; 24: 270-276Crossref PubMed Google Scholar, 17Rosenstreich DL Eggleston P Kattan M et al.Cockroaches in the asthma morbidity of inner-city children.N Engl J Med. 1997; 336: 1356-1363Crossref PubMed Scopus (821) Google Scholar, 21Wahn U. Indoor allergen exposure as a risk factor for sensitization in the first three years of life. J Allergy Clin Immunol In press.Google Scholar Perhaps the most important finding has been the clear evidence that there are communities in which a high prevalence of asthma is associated with indoor allergens other than dust mites. In some North American cities (e.g., Atlanta, Chicago, Detroit, Cleveland, New York, and Baltimore), sensitization to allergens from German cockroach is commonly associated with asthma among low income populations living in houses containing high concentrations of cockroach allergens.12Call RS Smith TF Morris E Chapman MD Platts-Mills TAE. Risk factors for asthma in inner city children.J Pediatr. 1992; 121: 862-866Abstract Full Text PDF PubMed Google Scholar, 17Rosenstreich DL Eggleston P Kattan M et al.Cockroaches in the asthma morbidity of inner-city children.N Engl J Med. 1997; 336: 1356-1363Crossref PubMed Scopus (821) Google Scholar, 22Gelber LE Seltzer LH Bouzoukis JK Pollart SM Chapman MD Platts-Mills TAE. Sensitization and exposure to indoor allergens as risk factors for asthma among patients presenting to hospital.Am Rev Respir Dis. 1993; 147: 573-578Crossref PubMed Google Scholar, 23Sarpong SB Hamilton RG Eggleston PA Adkinson Jr., NF Socioeconomic status and race as risk factors for cockroach allergen exposure and sensitization in children with asthma.J Allergy Clin Immunol. 1996; 97: 1393-1401Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar By contrast, in northern Scandinavia and in the mountain states of the United States, cats and/or dogs are the most important source of allergen related to asthma.11Sporik R Ingram JM Price W Sussman JH Honsinger RW Platts-Mills TAE. Association of asthma with serum IgE and skin-test reactivity to allergens among children living at high altitude: tickling the dragon's breath.Am J Respir Crit Care Med. 1995; 151: 1388-1392Crossref PubMed Google Scholar, 14Wickman M Nordvall SL Pershagen G Sundell J Schwartz B. House dust mite sensitization in children and residential characteristics in a temperate region.J Allergy Clin Immunol. 1991; 88: 89-95Abstract Full Text PDF PubMed Google Scholar, 15Munir AKM Bjorksten B Einarsson R Schou C Ekstrand-Tobin A Warner A et al.Cat (Fel d I), dog (Can f I) and cockroach allergens in homes of asthmatic children from three climatic zones in Sweden.Allergy. 1994; 49: 508-516Crossref PubMed Google Scholar In Arizona and central Australia, Alternaria has been reported to be the dominant allergen associated with asthma.24Peat JK Tovey CM Mellis CM Leeder SR Woolcock AJ. Importance of house dust mite and Alternaria allergens in childhood asthma: an epidemiological study in two climatic regions of Australia.Clin Exp Allergy. 1993; 23: 812-820Crossref PubMed Scopus (182) Google Scholar, 25Halonen M Stern DA Wright AL Tussig LM Martinez F. Alternaria as a major allergen for asthma in a desert environment.Am J Respir Crit Care Med. 1997; 155: 1356-1361Crossref PubMed Google Scholar, 26O'Hollaren MT Yunginger J Offord KP Somers MJ O'Connell EJ Ballard DJ et al.Exposure to an aeroallergen as a possible precipitating factor in respiratory arrest in young patients with asthma.N Engl J Med. 1991; 324: 359-363Crossref PubMed Google Scholar The studies on Alternaria are striking because there are no other reports suggesting that allergens found outdoors have played an important role in the increases in asthma. Sensitization to pollen allergens may be significantly associated with asthma in clinic or emergency department studies. However, in population-based studies using multiple regression, sensitization to grass, ragweed, or tree pollens has not been shown to be an independent risk factor for asthma.16Peat JK Tovey E Gray EJ Mellis CM Woolcock AJ. Asthma severity and morbidity in a population sample of Sydney schoolchildren, II: importance of house dust mite allergen.Aust N Z J Med. 1994; 24: 270-276Crossref PubMed Google Scholar, 27Sears MR Hervison GP Holdaway MD Hewitt CJ Flannery EM Silva PA. The relative risks of sensitivity to grass pollen, house dust mite, and cat dander in the development of childhood asthma.Clin Exp Allergy. 1989; 19: 419-424Crossref PubMed Google Scholar, 28Squillace SP Sporik RB Rakes G Couture N Lawrence A Merriam S et al.Sensitization to dust mites as a dominant risk factor for adolescent asthma: ordinal linear regression analysis of a population-based study.Am J Respir Crit Care Med. December. 1997; Google Scholar Overall, the observations strongly support the view that it is specific sensitization to indoor allergens rather than generalized IgE hyperresponsiveness that is associated with perennial asthma. It is clear that understanding the immune response to the foreign antigens found in domestic houses and the subsequent inflammatory events is central to both the investigation and treatment of asthma.BIOLOGYKnowledge of the biology and ecology of allergen-producing organisms is the starting point for the design, construction, and maintenance of healthy dwellings and for achieving effective allergen control regimes.Dust mitesA pictorial key to the identification of mites found in houses (which can be referred to as domestic mites) has been published.29Colloff MJ Spieksma FThM Pictorial keys for the identification of domestic mites.Clin Exp Allergy. 1992; 22: 823-830Crossref PubMed Google Scholar This includes both the house dust (or pyroglyphid) mites and storage mites, which can also contribute allergens to house dust. A database of the global distribution and abundance of mites in homes and their allergens has recently been established (D.MITEDATA).30Colloff MJ. The global distribution of major species of dust mites.Proceedings of the 3rd International Workshop on Indoor Allergens and Asthma, Cuenca, Spain. June 30-July 2, 1995; (UCB Institute of Allergy. In press)Google Scholar The database enables distribution maps of clinically important species in different parts of the world to be plotted and used to determine the frequency and abundance of mite species in different countries and localities. Computer models of the relationship between outdoor climate, indoor climate, building characteristics, and dust mite population size have been designed to aid mite eradication and allergen reduction in homes.30Colloff MJ. The global distribution of major species of dust mites.Proceedings of the 3rd International Workshop on Indoor Allergens and Asthma, Cuenca, Spain. June 30-July 2, 1995; (UCB Institute of Allergy. In press)Google Scholar, 31van Lynden-van Nes, Kort AMT, Koren HSM, Pernot CEE, van Bronswijk JEMH. Limiting factors for growth and development of domestic mites. In: van Bronswijk JEMH, Pauli G, editors. An update on long-lasting mite avoidance. GuT, Aachen; p. 13-25.Google Scholar There is a need for basic life-history data (developmental rates, fecundity, sensitivity to humidity) on mites, such as Blomia tropicalis, which have become recognized as important allergen sources in tropical and subtropical areas of the world (e.g., South and Central America, southern states of the United States, and the Far East). Mite responses to humidity are temperature dependent, and this is important when comparing dust mite populations in homes in temperate versus tropical or subtropical regions.32Maelzer DA. Water, temperature and house-dust mites.in: Mites, asthma and domestic design: proceedings of a conference held at the Powerhouse Museum. University of Sydney, (Australia)15th March, 1993: 9-18Google Scholar Recent work has provided a basis for modeling the effects of humidity and temperature on population dynamics of dust mites.32Maelzer DA. Water, temperature and house-dust mites.in: Mites, asthma and domestic design: proceedings of a conference held at the Powerhouse Museum. University of Sydney, (Australia)15th March, 1993: 9-18Google Scholar, 33Arlian LG. Water balance and humidity requirements of house dust mites.in: House dust mite [Special Issue]. Exp Appl Acarol. 16. 1992: 15-35Google ScholarEffective control of dust mites requires understanding why some populations persist at high densities and others at low densities.34Arlian LG Dippold JS. Development and fecundity of Dermatophagoides farinae (Acari: Pyroglyphidae).J Med Entomol. 1996; 33: 257-260Crossref PubMed Google Scholar, 35Mollett JA Robinson WH. Dispersal of American house dust mites (Acari:Pyroglyphidae) in a residence.J Med Entomol. 1996; : 844-847PubMed Google Scholar, 36McGregor P. Population dynamics for house dust mite researchers.in: Mites, asthma and domestic design II. University of Sydney, (Australia)1995: 22-25Google Scholar, 37Colloff MJ. Age, structure and dynamics of house dust mite populations.in: House dust mite [Special Issue]. Exp Appl Acarol. 16. 1992: 49-74Google Scholar Modeling of populations may have predictive value through the use of surrogates of population growth, such as measurement of the age structure of the mite population. Data on the proportions of eggs, larvae, nymphs, and adults in a population also can be used to predict whether that population is increasing or decreasing in size and how successful different control measures are likely to be.36McGregor P. Population dynamics for house dust mite researchers.in: Mites, asthma and domestic design II. University of Sydney, (Australia)1995: 22-25Google Scholar, 37Colloff MJ. Age, structure and dynamics of house dust mite populations.in: House dust mite [Special Issue]. Exp Appl Acarol. 16. 1992: 49-74Google Scholar The structure of mite fecal particles is maintained by a peritrophic membrane. This is important because group 1 mite allergens become airborne in the form of intact fecal particles.1Platts-Mills TAE De Weck A. Dust mite allergens and asthma—a world wide problem.Bull WHO. 1989; 66: 769-780Google Scholar The function of this membrane that is characteristic of arthropods is not fully understood. It has been suggested that the membrane may help to protect the hind gut from physical damage; may be relevant to coprophagia; or may act as a functional antioxidant. On the other hand, in some insects the membrane is part of the mechanism that protects the host from invasion by microorganisms in the food.38Sieber KP Huber M Kaslow D Banks SM Torii M Aikawa M et al.The peritrophic membrane as a barrier: its penetration by Plasmodium gallinaceum and the effect of a monoclonal antibody to ookinetes.Exp Parasitol. 1991; 72: 145-156Crossref PubMed Scopus (52) Google ScholarCockroachesSpatial analysis techniques as well as probability contours have been used to model distribution of cockroaches and their allergens in buildings in relation to changes in the distribution of food resources.39Brenner RJ. Preparing for the 21st century: research methods in developing management strategies for arthropods and allergens in the structural environment.in: Proceedings of the 1st International Conference on Insect Pests in the Urban Environment. BPCC, Wheatons Ltd., Exeter,, U.K1993: 57-69Google Scholar These techniques rely on the assumption that allergenic organisms are clumped, not randomly distributed, in relation to the availability of resources and have major implications for explaining the distribution of both dust mite allergens and cockroach allergens within the home. The biology of cockroaches is highly relevant to control strategies.40Cochran DG. Relevance of resistance ratios to operational control in the German cockroach (Dictyoptera, Blatelidae)..J Econ Entomol. 1996; 89: 318-321Google Scholar The traditional use of boric acid as a bait has been explained recently because this compound leads to progressive damage to the foregut, so that the roaches starve.41Cockran DG. The effect of boric acid on Blattella germanica.Experimentia. 1995; 51: 561Crossref PubMed Scopus (28) Google Scholar The effect of other insecticides also may be relevant because glutathione transferase is a scavenging enzyme, and increased production is one mechanism of resistance to organophosphate insecticides.42Hemingway J Small GJ. Resistance mechanisms in cockroaches: the key to control strategies.in: Proceedings of the 1st International Conference on Insect Pests in the Urban Environment.1993: 141-152Google Scholar Since it also has been shown that this enzyme is a potent allergen, there is a potential for resistant organisms to produce more allergen.Cat allergensHistopathologic studies have demonstrated clearly that the cat allergen, Fel d 1, which is found on cat hair, is produced in cat sebaceous glands and salivary glands; in addition, large amounts of Fel d 1 have been demonstrated in cat anal glands.43Dornelas de Andrade A Birnbaum J Magalon JP Lanteaume A Charpin D et al.Fel d 1 levels in cat anal glands.Clin Exp Allergy. 1996; 26: 178-180Crossref PubMed Scopus (27) Google Scholar Recent studies suggest that Fel d 1 production by glands in male cats is under hormonal control. Castration leads to a rapid decrease in Fel d 1 production, and injection of testosterone returns Fel d 1 to baseline levels.44Zielonica T Charpin D Berba D Luciani P Casanova D Vervloet D. Effects of castration and testosterone on Fel d 1 production by sebaceous glands of male cats.Clin Exp Allergy. 1994; 12: 1169-1173Crossref Google Scholar The clinical relevance of this observation is not clear, because in the United States the great majority of symptomatic patients are exposed to cats (or dogs) that have been neutered.45Miller JD Bell JB Vandernoot D. Castration of pets does not prevent allergy to pets.Clin Exp Allergy. 1995; 25: 575Crossref PubMed Google Scholar Fel d 1 production varies strikingly in individual cats. Future research in this area could address the effects of hormonal change in female cats; the effects of age on allergen production by domestic animals; genetic control of Fel d 1 production; other methods of decreasing production of cat allergens; and the biologic role of Fel d 1.IMMUNOCHEMISTRY AND MOLECULAR BIOLOGYAllergen identification and nomenclatureIndoor allergens that are included in the WHO/IUIS nomenclature are listed in Table I.46King TP Hoffman D Lowenstein H Marsh DG Platts-Mills TAE Thomas WR. Allergen nomenclature.Bull WHO. 1994; 72: 797-806PubMed Google Scholar These allergens have been purified from aqueous extracts or produced as recombinant proteins and, in most cases, nucleotide or amino acid sequences have been determined. Since the last workshop report in 1991, cloning of indoor allergens has progressed rapidly and many allergens have been identified and sequenced. Major developments include (1) cloning of allergens from mites (Dermatophagoides spp., Lepidoglyphus destructor, and B. tropicalis), German and American cockroaches, and dog; (2) establishing the biologic function and allergenic importance of these allergens; and (3) continued production of monoclonal antibodies and development of immunoassays for indoor allergens. Table IStructural and functional properties of indoor allergensSourceAllergen*MWFunction†Sequence‡House dust miteDermatophagoides spp.Group 1§25 kdCysteine proteasecDNAGroup 2§14 kd(Epididymal protein)cDNAGroup 3§~30 kdSerine proteasecDNADer p 4~60 kdAmylaseProteinGroup 5§14 kdUnknowncDNADer p 625 kdChymotrypsinProteinGroup 7§22-28 kdUnknowncDNADer p 826 kdGlutathione-S-transferasecDNADer p 924 kdCollagenolytic serine proteasecDNAGroup 10§36 kdTropomyosincDNAEuroglyphus mayneiEur m 125 kdCysteine proteasePCRBlomia tropicalisBlo t 5§14 kdUnknowncDNALepidoglyphus destructorLep d 2§14 kd(Epididymal protein)Protein and cDNAMammalsFelis domesticusFel d 1§36 kd(Uteroglobin)PCRCanis familiarisCan f 1§25 kd(Taste perception)cDNACan f 2§27 kdCalycincDNAMus musculusMus m 119 kdPheromone binding proteincDNARattus norvegicusRat n 1§19 kdPheromone binding proteincDNACockroachBlattella germanicaBla g 1§20-25 kdUnknowncDNABla g 2§36 kdAspartic proteasecDNABla g 421 kdCalycincDNABla g 522 kdGlutathione transferasecDNAPeriplaneta americanaPer a 120-25 kdUnknowncDNAPer a 3§72-78 kdArylphorin269Wu CH Lee MF Liao SC Luo SF. Sequencing analysis of cDNA clones encoding the American cockroach Cr-PI allergens.J Biol Chem. 1996; 30: 17937-17943Google ScholarcDNA*Revised nomenclature proposed by the WHO/IUIS subcommittee.1Platts-Mills TAE De Weck A. Dust mite allergens and asthma—a world wide problem.Bull WHO. 1989; 66: 769-780Google Scholar†Based on sequence similarity searches of protein and nucleic acid databases. In most cases the allergen function has been confirmed by testing for biologic activity (e.g., enzyme activity). Allergens in parentheses show structural homology, but functional activity has not been confirmed or established.‡Method given for full sequence determination, where available. However, protein sequences are incomplete; usually N-terminal or internal peptide sequences have been determined.§Allergens for which monoclonal antibodies are available and are suitable for immunoassay purposes. Open table in a new tab Several candidate mite allergens for inclusion in the WHO/IUIS nomenclature were considered by the workshop. It was recommended that the 14 to 15 kd L. destructor allergen, formerly identified as Lep d 1, should be reclassified as Lep d 2 because this allergen showed greater than 40% sequence identity to the group 2 allergens of Dermatophagoides spp. and had the same molecular weight.47Varela J Ventas P Carreira J Barbas JA Gimenez-Gallego G Polo F. Primary structure of Lep d 1, the main Lepidoglyphus destructor allergen. [This allergen is now called Lep d 2.].Eur J Biochem. 1994; 225: 93-97Crossref PubMed Scopus (28) Google Scholar, 48Schmidt M Olsson S van der Ploeg I van Hage-Hamsten M. cDNA analyses of the mite allergen Lep d 1 identifies two different isoallergens and variants. (This allergen is now called Lep d 2).FEBS Lett. 1995; 370: 11-14Abstract Full Text PDF PubMed Scopus (37) Google Scholar It also was recommended that three newly identified Dermatophagoides spp. allergens were sufficiently well characterized by sequence data, protein chemistry, and IgE antibody binding data to be added to the nomenclature: glutathione-S-transferase (Der p 8), collagenolytic serine protease (Der p 9), and tropomyosin (Der p 10 and Der f 10) (Table I).49O'Neill GM Donovan GR Baldo BA. Cloning and characterization of a major allergen of the house dust mite, Dermatophagoides pteronyssinus, homologous with glutathione S-transferase.Biochem Biophys Acta. 1996; 1219: 521-528Google Scholar, 50King C Simpson RJ Moritz RT Thompson PJ Stewart GA. Isolation and characterization of a novel collagenolytic serine protease, Der p 9, from the house dust mite, Dermatophagoides pteronyssinus..J Allergy Clin Immunol. 1996; 98: 739-747Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar, 51Aki T Kodama T Fujikawa A Miura K Shigeta S Wada T et al.Immunochemical characterization of recombinant and native tropomyosins as a new allergen from the house dust mite, Dermatophagoides farinae..J Allergy Clin Immunol. 1995; 96: 74-83Abstract Full Text Full Text PDF PubMed Scopus (122) Google Scholar The group 10 tropomyosin allergens appear to be largely responsible for IgE antibody cross-reactivity between mites and other invertebrates such as shrimp, chironomids, and cockroaches.52Witteman AM Akkerdass JH van Leeuwen J van der Gee JS Aalberse RC. Identification of a cross-reactive allergen (presumably tropomyosin) in shrimp, mite and insects.Int Arch Allergy Immunol. 1994; 105: 56-61Crossref PubMed Google ScholarMolecular cloning also has identified allergens from B. tropicalis, Euroglyphus maynei and Tyrophagous putrescentiae. Although a commercial RAST assay for E. maynei has been marketed, extracts of these species are not widely available and recombinant DNA techniques may provide the best approach to producing their allergens. A major B. tropicalis allergen, Blo t 5, has been identified that shows an approximate 40% amino acid sequence homology to Der p 5.53Arruda LK Vailes LD Platts-Mills TAE Fernandez-Caldes E Montealegre F Chua KY et al.Sensitization to Blomia tropicalis in patients with asthma and identification of allergen Blo t 5.Am J Respir Crit Care Med. 1997; 155: 343-350Crossref PubMed Google Scholar, 54Caraballo L Avjioglu A Marrugo J Puerta L Marsh D. Cloning and expression of complementary DNA coding for an allergen with common antibody-binding specificities with three allergens of the house dust mite Blomia tropicalis.J Allergy Clin Immunol. 1996; 98: 573-579Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar The prevalence of IgE antibody to Blo t 5 is 60% to 70% among patients from tropical countries (e.g., Brazil, Colombia, Singapore) who can be exposed to high levels of B. tropicalis in their homes.55Arruda LK Chapman MD. A review of recent immunochemical studies of Blomia tropicalis and Euroglyphys maynei allergens.Exp Appl Acarol. 1992; 16: 129-140Crossref PubMed Scopus (22) Google Scholar, 56Fernandez-Caldas E Puerta L Mercado D Lockey RF Caraballo LR. Mite fauna, Der p I, Der f I and Blomia tropicalis allergen levels in a tropical environment.Clin Exp Allergy. 1993; 23: 292-297Crossref PubMed Google Scholar, 57Fernandez-Caldas E Baena-Cagnani CE Lopez JH Malka S Naspitz CK Lockey RF. Cutaneous sensitivity to six mite species in asthmatic patients from five Latin countries.J Invest Allergol Clin Immunol. 1993; 3: 245-249PubMed Google Scholar, 58Van Hage-Hamsten M Machado L Barros MT Johansson SGO. Immune response to Blomia kulagini and Dermatophagoides pteronyssinus in Sweden and Brazil.Int Arch Allergy Appl Immunol. 1990; 91: 186-191Crossref PubMed Google Scholar Other B. tropicalis