Immunotherapy of allergic disease.
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Biomedical subjects
Publications and source records attributed to M Focke.
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BACKGROUND: IgE antibodies against carbohydrate epitopes have been identified recently as a major cause of in vitro double positivity to honeybee (HB) and vespid venom in patients with stinging-insect allergy. As these antibodies possibly have low clinical relevance they may be misleading in the diagnosis of venom allergy. OBJECTIVE: To confirm the role of carbohydrate epitopes in double positivity and to locate the responsible glycoallergens in HB and yellow jacket (YJ) venom by western blot. METHODS: Immunoblot inhibition using HB venom, YJ venom and two glycoprotein sources displaying 1-3-fucosylated N-glycans (i.e. oilseed rape (OSR) pollen, and the synthetic neo-glycoprotein fucosylated/xylosylated N-glycans from bromelain coupled to bovine serum albumin (MUXF-BSA)) as inhibitors were performed with sera from 15 double-positive patients with stinging-insect allergy. Additionally, reactivity with blotted hymenoptera venoms of a carbohydrate-specific rabbit antiserum against OSR pollen was investigated. RESULTS: Major venom glycoallergens binding with carbohydrate-specific human IgE and rabbit IgG were detected in HB venom at 42 (hyaluronidase (HYA)), 46, 65 and 95 kDa, and in YJ venom at 38 and 43 kDa (HYA). Antibody binding to these allergens was completely lost after periodate treatment. Glycans of HB phospholipase were bound by patients' IgE only after protein denaturation. In 10 of the 15 patients the reactivity was with the second venom because of carbohydrates alone. The high-molecular-weight glycoallergens identified in HB venom probably correspond to similar proteins described earlier, including allergens B and C. The 38-kDa YJ allergen might represent a homologue of V mac 3. CONCLUSIONS: The data confirm the proposed role of carbohydrate-specific IgE in double positivity to HB and YJ venom and shed new light on some previously described minor hymenoptera allergens of uncertain clinical significance. The consideration of carbohydrate-specific IgE may allow to discriminate between patients with potentially relevant and patients with non-relevant double sensitization.
BACKGROUND: Ornamental Ficus benjamina (FB) has been recognized as a new indoor allergen. Little is known about the prevalence in moderately exposed subjects and the proposed association with fruit and Hevea latex hypersensitivity. OBJECTIVE: To study the prevalence of FB sensitization and the relationship with Hevea latex allergy, to identify cross-reacting fruits, and to characterize the responsible allergens. METHODS: A skin prick test solution prepared from FB latex (200 microg/mL) was included in our routine screening programme for suspect inhalant allergy. Patients reacting with the FB extract were further skin tested with exotic fruits by the prick-to-prick method. Inhibition of fig and FB CAP by FB latex, fig (Ficus carica), kiwi, the thiolproteases ficin and papain, Hevea latex and rHev b 6.02 (hevein) was performed in selected patients. RESULTS: Of 2662 patients with a positive skin test to any aeroallergen, 66 (2.5%) reacted with FB. Ten patients showed isolated sensitization to FB. Although FB-positive subjects were more often co-sensitized to Hevea latex than FB-negative (10.6% vs 3.8%, P< 0.01), nearly 90% tested negative for Hevea latex. Sensitization to FB was specifically associated with positive skin tests to fresh fig (83%), dried fig (37%), kiwi fruit (28%), papaya (22%), avocado (19%), banana (15%), and pineapple (10%) (n = 54). Clinical reactions were reported mainly from fresh and dried fig and kiwi (47%, 60%, and 64%, respectively, of skin test-positive patients), including seven patients with systemic reactions (urticaria, angiooedema, asthma). CAP to fig in 11 patients with clinical fruit allergy was inhibited on average by 87% by FB latex, 89% by fresh fig, 80% by dried fig, 38% by kiwi (100 microg/mL each), and by 59% and 44% by ficin and papain (50 microg/mL), respectively. No inhibition was obtained with Hevea latex and rHev b 6.02. CAP to FB was inhibited on average by 95% by FB, 60% by fresh fig, 41% by ficin, 29% by papain, and less than 7% by rubber latex allergens. CONCLUSIONS: Sensitization to FB latex is found in 2.5% of atopic individuals and mostly occurs independently of Hevea latex allergy. Sensitization is commonly associated with allergic reactions to figs and other tropical fruits ('Ficus-fruit syndrome'). This cross-reactivity is mediated at least in part by thiolproteases.
BACKGROUND: Almost 100 million allergic patients are sensitized to the major birch pollen allergen, Bet v 1, a 17 kDa protein containing most of the IgE epitopes present in pollens of trees belonging to the Fagales order and plant-derived food. OBJECTIVE: Our aim was to develop an approach for the rational design of B cell epitope-derived, non-allergenic peptide allergy vaccines. METHODS: According to the three-dimensional (3-D) structure of birch pollen allergen, Bet v 1, six peptides comprising 25-32 preferably solvent-exposed amino acids were synthesized. RESULTS: Because of lack of secondary structure, the peptides showed no allergenic activity in allergic patients. In a mouse model of birch pollen allergy, peptide vaccination induced Bet v 1-specific IgG and prevented IgE-mediated allergic sensitization to Bet v 1. The protective role of peptide-induced blocking antibodies is demonstrated by inhibition of allergic patients IgE binding to the allergen and by blocking of allergen-induced basophil degranulation. CONCLUSION: Our results indicate the mechanistic importance of blocking antibodies for allergy vaccination and present a B cell epitope-based approach for the rational design of safe peptide allergy vaccines whenever the structure of the disease-eliciting allergen is known.
BACKGROUND: Allergy to houseflies is rare. We report a case of respiratory allergy from occupational exposure to houseflies in a farmer. CASE REPORT: A 30 year-old female farmer with a long-standing history of grass pollen allergy observed for 2 years rhino-conjunctivitis and mild asthma when entering livestock stables and barns. Allergy retesting revealed sensitization to various pollens but not to animal danders. Houseflies (Musca domestica) occurring on the farm in great quantity were suspected by the farmer herself as the causative agent. RESULTS: Skin prick testing with housefly was positive in the patient and negative in four controls. Experimental radioallergosorbant test was class 3 positive. Sensitization to house dust mite, storage mites and cockroach was not detectable. Western blots with housefly extracts revealed immunoglobulin E (IgE)-binding to bands of 70, 50, and approximately 16 kDa. Tropomyosin in the housefly extract (35 kDa) was recognized by a tropomyosin reference serum but not by the patient. In enzyme-linked immunosorbent assay (ELISA) inhibition assays using housefly as the solid phase, IgE-binding of the patient was inhibited by 75% by M. domestica and by 44% by the closely related lesser housefly (Fannia canicularis), but not by extracts from blowfly (Lucilia spp.), fruit fly (Drosophila spp.), horsefly (Haematopota pluvialis) and mosquito (Culex pipiens). The IgE-binding of the tropomyosin control serum was inhibited by 60-80% by all species. CONCLUSIONS: In accordance with previous reports, this case demonstrates that respiratory sensitization to insects may be highly specific. According to ELISA inhibition, cross-sensitization in the present case was restricted to species of the family of true flies (Muscidae).
BACKGROUND: Anaphylactic reactions to fig fruits (Ficus carica) have been reported from subjects sensitized to Ficus benjamina (FB) latex allergens. Figs may also be involved in the latex-fruit syndrome. OBJECTIVE: To study the immunologic relationship between fig fruit, Ficus benjamina, natural rubber latex (Hevea brasiliensis), and other tropical fruits. METHODS: RAST inhibition and Western blotting with FB and fruit extracts was performed in five patients with oral allergy syndrome (OAS) or anaphylaxis after the ingestion of figs and one patient with symptoms from exposure to FB trees. Co-sensitization to rubber latex and tropical fruits (kiwi, banana, avocado, papaya, pineapple, mulberry) was studied by skin testing. RESULTS: RAST to FB was inhibited >95% by FB extracts and 16-65% (mean 49%) by extracts from fresh fig. RAST to fig fruit was inhibited >95% by FB and fresh fig, 63-97% (mean 86%) by dried fig, and 0-84% (mean 35.5%) by kiwi fruit. FB and fig extracts lost most of their allergenicity when denatured by heat (95 degrees C) or reduced by dithiothreitol. Western blotting after non-reducing gel electrophoresis revealed IgE binding to proteins of 22 and 28-34 kDa in FB latex; however, no corresponding allergens could be detected in fig extracts. Positive skin tests were obtained most often with kiwi fruit, papaya, and avocado. Sensitization to rubber latex could not be demonstrated in any of the patients. RAST to papain was positive in three of five patients. CONCLUSIONS: Allergic reactions to fresh or dried figs can present as a consequence of primary sensitization to airborne FB allergens independent of sensitization to rubber latex allergens. Kiwi fruit, papaya, and avocado as well as pineapple and banana may be other fruits associated with sensitization to Ficus allergens.
BACKGROUND: Patients suffering from allergic rhinoconjunctivitis and dyspnoea during summer may exhibit these symptoms after contact with flowers or dietary products of the elderberry tree Sambucus nigra. OBJECTIVE: Patients with a history of summer hayfever were tested in a routine setting for sensitization to elderberry. Nine patients having allergic symptoms due to elderberry and specific sensitization were investigated in detail. We studied the responsible allergens in extracts from elderberry pollen, flowers and berries, and investigated cross-reactivity with allergens from birch, grass and mugwort. METHODS: Sera from patients were tested for IgE reactivity to elderberry proteins by one-dimensional (1D) and 2D electrophoresis/immunoblotting. Inhibition studies with defined allergens and elderberry-specific antibodies were used to evaluate cross-reactivity. The main elderberry allergen was purified by gel filtration and reversed-phase HPLC, and subjected to mass spectrometry. The in-gel-digested allergen was analysed by the MS/MS sequence analysis and peptide mapping. The N-terminal sequence of the predominant allergen was analysed. RESULTS: 0.6% of 3668 randomly tested patients showed positive skin prick test and/or RAST to elderberry. IgE in patients' sera detected a predominant allergen of 33.2 kDa in extracts from elderberry pollen, flowers and berries, with an isoelectric point at pH 7.0. Pre-incubation of sera with extracts from birch, mugwort or grass pollen rendered insignificant or no inhibition of IgE binding to blotted elderberry proteins. Specific mouse antisera reacted exclusively with proteins from elderberry. N-terminal sequence analysis, as well as MS/MS spectrometry of the purified elderberry allergen, indicated homology with ribosomal inactivating proteins (RIPs). CONCLUSION: We present evidence that the elderberry plant S. nigra harbours allergenic potency. Independent methodologies argue for a significant homology of the predominant 33.2 kDa elderberry allergen with homology to RIPs. We conclude that this protein is a candidate for a major elderberry allergen with designation Sam n 1.
BACKGROUND: Profilins are recognised by IgE of about 20% of patients allergic to birch pollen and plant foods. They are ubiquitous intracellular proteins highly cross-reactive among plant species. Therefore, they were called panallergens and are made responsible for cross-sensitisation between plant pollen and food. OBJECTIVES: The aim of the present study was to clone the cDNAs encoding profilins from bell pepper and tomato, to produce and purify the recombinant proteins and to compare their IgE-binding capacities to those of the natural proteins. METHODS: cDNA clones coding for profilin were obtained by RT-PCR from total RNA of tomato and bell pepper fruits, sequenced and expressed as non-fusion proteins in ESCHERICHIA COLI. The recombinant profilins were subsequently purified and tested for IgE-binding and inhibition capacity with sera from 34 food-allergic patients. Possible oligomerisation of recombinant profilins was investigated by HPLC analysis and its influence on IgE binding assayed by ELISA. RESULTS: The open reading frame from both profilins encompasses 393 bp with a predicted molecular mass of 14,184 kD and a pI of 4.44 for bell pepper profilin (Cap a 2) and 14,257 kD and a pI of 4.46 for the profilin from tomato (Lyc e 1). The two protein sequences display 91% identity, whereas tomato profilin from pollen shares only 75% identity with tomato fruit profilin. Eleven out of 34 food-allergic patients (32%) display IgE binding to both purified profilins. Preincubation of a serum pool with either purified rCap a 2 or rLyc e 1 nearly abolished IgE binding to natural Cap a 2 and Lyc e 1, respectively. In addition, purified recombinant Cap a 2 was able to inhibit IgE-binding to rLyc e 1 by approximately 50%, whereas rLyc e 1 completely blocked IgE-binding to rCap a 2 in cross-inhibition assays. HPLC analysis showed that in solution Cap a 2 and Lyc e 1 can be found predominantly as dimers, which can be partially reduced to monomers by addition of dithiothreitol (DTT). In ELISA DTT-treated Lyc e 1 displayed a clearly lower IgE-binding capacity than untreated profilin. CONCLUSIONS: Purified rCap a 2 and rLyc e 1 proved to be valuable tools for studying cross-reactivity to profilins in patients allergic to pollen and food.
BACKGROUND: Germins and the related germin-like proteins (GLPs) are glycoproteins expressed in many plants in response to biotic and abiotic stress. To test the potential impact of germins and GLPs, recombinant germin from Triticum aestivum (tGermin) and GLPs from Arabidopsis thaliana (tGLP), both produced in transformed tobacco plants, were used. METHODS: Sera from 82 patients with type I allergy to birch, grass or mugwort pollen and/or wheat were tested in immunoblot for IgE binding to tGermin and tGLP, and the IgE reactivity after chemical and enzymatic deglycosylation was analysed. The biological activity of tGermin and tGLP was determined in a histamine release assay and in skin prick testing (SPT). RESULTS: In an immunoblotting assay, 24 out of 82 tested sera (29.26%) from allergic patients showed IgE-binding to tGermin, and 18 of these sera (21.95%) displayed also IgE-binding to tGLP. The deglycosylation experiments indicated that glycan moieties contribute significantly to the IgE-binding of tGermin and tGLP. Both tGermins and tGLP induced specifically histamine release in an in vitro assay as well as in SPT. CONCLUSION: Our in vitro and in vivo findings demonstrate that germin and GLPs are capable to bind IgE most likely via carbohydrate determinants, and represent allergenic molecules.
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Worldwide more than 200 million individuals are allergic to group 1 grass pollen allergens. We have used the major timothy grass pollen allergen Phl p 1, which cross-reacts with most grass-, corn-, and monocot-derived group 1 allergens to develop a generally applicable strategy for the production of hypoallergenic allergy vaccines. On the basis of the experimentally determined B cell epitopes of Phl p 1, we have synthesized five synthetic peptides. These peptides are derived from the major Phl p 1 IgE epitopes and were between 28-32 amino acids long. We demonstrate by nuclear magnetic resonance that the peptides exhibit no secondary and tertiary structure and accordingly failed to bind IgE antibodies from grass pollen allergic patients. The five peptides, as well as an equimolar mixture thereof, lacked allergenic activity as demonstrated by basophil histamine release and skin test experiments in grass pollen allergic patients. When used as immunogens in mice and rabbits, the peptides induced protective IgG antibodies, which recognized the complete Phl p 1 wild-type allergen and group 1 allergens from other grass species. Moreover, peptide-induced antibodies inhibited the binding of grass pollen allergic patients IgE antibodies to the wild-type allergen. We thus demonstrate that synthetic hypoallergenic peptides derived from B cell epitopes of major allergens represent safe vaccine candidates for the treatment of IgE- mediated allergies.
Chelating agents in protective barrier creams have often been used in the prevention of allergic contact dermatitis to nickel. In a pilot study, we demonstrated the preventive effect of 10% diethylenetriaminepentaacetic acid (DTPA) in an oil-in-water emulsion in nickel-sensitized patients. Now we reproduced these results in a randomized, double-blind study. Additionally, we investigated the efficacy of the barrier cream in other clinically relevant metal allergies. Individuals sensitized to various metals had a significant decrease in positive patch test reactions after pre-treatment with the DTPA-cream: 2.5% nickel sulfate (24/28 positive without pre-treatment versus 1/28 with pre-treatment; p<0.0001), 5% nickel sulfate (30/32 versus 15/32; p=0.0003), 1% cobalt chloride (19/20 versus 6/20; p=0.001) and 5% copper sulfate (13/14 versus 5/14; p=0.02). However, the cream had no protective effect with 1% palladium chloride (17/23 versus 16/23) and with 0.5% potassium dichromate (9/13 versus 7/13). We conclude that the DTPA-cream clearly abrogates positive patch test reactions in nickel-, cobalt- and copper-sensitized subjects and that it may therefore be helpful in the management of allergic contact dermatitis.
BACKGROUND: Patch testing to fragrances is an important step in the diagnosis of fragrance allergy. OBJECTIVES: To determine the usefulness of adding propolis to the European standard series to test for fragrance allergy. PATIENTS AND METHODS: A total of 2660 consecutive patients were patch tested with a standard patch test series; 747 suspected of fragrance allergy were tested further with a special fragrance series. RESULTS: The positive results to the standard series in 2660 patients were: fragrance mix 243 (9.1%), Myroxylon Pereirae [balsam of Peru] 144 (5.4%), colophony 32 (1.2%); these fragrance mixtures are used as screening substances for fragrance allergy in the European standard series. Propolis, also known as bee's glue, was also an important allergen in this locally revised standard series (n = 35, 1.3%). Positive reactions to the aforementioned allergens were associated significantly among each other (P < 0.01, chi2-test) and did not differ between the sexes. The primary locations of dermatitis in patients with a positive test to one or more fragrance allergens (n = 162) among those suspected of fragrance allergy (n = 747) were: face 46.9%, hands 23.5%, neck 17.9%, axillae 12.3%; 92 of the 747 patients suspected of fragrance allergy had positive skin tests to the special fragrance series comprising the eight constituents of the fragrance mix (most frequent: isoeugenol 5.4%, oakmoss absolute 5.0%, eugenol 2.5%) and 14 other fragrance allergens (most frequent: clove oil 1.6%, lemon grass oil 0.8%, cedar wood oil 0.7%). The additional value of propolis as another screening substance for fragrance allergy in these patients was low. The likelihood of a reaction to one or more of the extra fragrance allergens increased with the number of reactions to fragrance screening allergens in the standard series. CONCLUSIONS: The number of positive reactions to fragrance screening allergens in a standard patch test series may be used as a rule of thumb for predicting a positive outcome of a more detailed testing to fragrances. Propolis is an important allergen in its own right but its value as a screening substance for fragrance allergy is limited.
A young girl presented with a hypopigmentation in the shape of the sun. During a holiday in Egypt 3 months before a non-permanent henna tattoo had been applied on her right upper arm. Three to 4 days later there was a severe cutaneous reaction followed by massive swelling of the arm. The lesion took 6 weeks to subside. Patch testing revealed positive reactions to para-phenylenediamine (PPD) but not to henna or any other standard allergen. Especially in Arabic countries PPD is a common additive in natural henna preparations to enhance the weak colouring properties of the natural henna dye. We conclude that henna preparations may contain 'hidden' allergens, such as PPD, which can provoke severe cutaneous reaction without any cosensitization to the henna dye itself.
BACKGROUND: Up to 50% of patients with stinging-insect allergy have double-positive RAST results to honeybee and yellow jacket (YJ) venom. True double sensitization and crossreactivity through venom hyaluronidases are considered main reasons for this multiple reactivity. OBJECTIVE: We investigated the role of antibodies against cross-reactive carbohydrate determinants in venom double positivity. METHODS: CAP inhibition experiments were performed with crude oilseed rape (OSR) and timothy grass pollen extracts and a neoglycoprotein construct displaying a MUXF glycan, as present in pineapple-stem bromelain (MUXF-BSA). CAP to OSR was used as a rough measure for carbohydrate-specific IgE in individual sera. RESULTS: CAP results to OSR pollen were positive in 2 of 14 single-positive honeybee venom sera, 2 of 16 single-positive YJ venom sera, and 33 (80.5%) of 41 double-positive sera (P < .00001, chi(2) test). CAP inhibition was performed in 16 selected patients with a CAP class of 3 or higher to both venoms. In 9 of 11 patients with a highly positive CAP result to OSR (CAP score to OSR > CAP score to second venom), pollen extracts, MUXF-BSA, or both were able to completely inhibit IgE binding to one of the venoms, whereas this was not the case in 5 patients with a negative or weakly positive CAP result to OSR (CAP score to OSR < CAP score to second venom). CONCLUSIONS: The data suggest that carbohydrate-specific IgE is a major cause for the double positivity to honeybee and YJ venom seen in patients with Hymenoptera allergy. Because these antibodies may have low clinical relevance, they may severely impede the correct diagnosis of Hymenoptera venom allergy.
BACKGROUND: Positive patch tests to copper sulfate are regularly observed, although copper is reported as a rare allergen with a low sensitizing potential. Usually they are claimed to be irritant and unspecific. OBJECTIVE: The aim of this study was to assess the relevance and the diagnostic value of positive reactions to copper. METHODS: A total of 2660 routine patch tests were analyzed for positive reactions to copper and other metal allergens: copper, 3.53%; nickel, 21.02%; palladium, 5.90%; cobalt, 3.31%. RESULTS: Reactions to copper and nickel were highly significantly associated with each other. Twenty-six patients with a positive routine test to copper were retested. The reproducibility was modest (38%), but again significantly associated with nickel sensitization. CONCLUSION: These clinical data support a copper-nickel cross-reactivity concept on T-cell level based on recently published molecular data. We conclude that positive patch tests to copper are mostly specific; however, they are usually of low clinical relevance.
BACKGROUND: Sildenafil citrate (Viagra), a drug used to treat erectile dysfunctions, causes adverse reactions such as headache, flushing or nasal congestion. Sildanefil's potency as inhibitor of diamine oxidase was investigated, as side effects may also be induced by histamine itself due to an impaired histamine metabolism. METHODS: Placental diamine oxidase inhibition experiments were performed with consecutive dilutions of sildenafil citrate (10(-5) to 10(-9) mol/l). In 9 male volunteers in vivo diamine oxidase inhibition was investigated after taking 100 mg sildenafil (Viagra). RESULTS: Sildenafil citrate did not inhibit placental diamine oxidase either in vitro or in vivo. However, infusion of 300 mg of cimetidine inhibited diamine oxidase activity by 27 +/- 7% 15 min after infusion, demonstrating that drugs may inhibit diamine oxidase in vivo. CONCLUSION: As side effects of sildenafil are not caused due to inhibition of diamine oxidase, sildenafil citrate seems to be harmless for patients suffering from histamine intolerance.