Analysis of the antibody responses induced by subcutaneous injection immunotherapy with birch and Fagales pollen extracts adsorbed onto aluminum hydroxide.

BACKGROUND: Allergen-specific subcutaneous immunotherapy (SCIT) is an antigen-specific therapy of IgE-mediated allergies. In the present study, we analyze the epitope specificities of antibody responses induced by SCIT with allergen extracts from pollen of trees belonging to the order Fagales (birch, alder, hazel) adsorbed onto aluminum hydroxide. METHODS: The IgE, IgG1-4 and IgA responses to defined recombinant allergens (birch pollen: Bet v 1; alder pollen: Aln g 1; hazel pollen: Cor a 1; apple: Mal d 1) as well as to Bet v 1-derived recombinant fragments and synthetic peptides were analyzed in sera from patients who had undergone SCIT for different periods of time. RESULTS: Long-term SCIT (>1 year; cumulative dose >1,000,000 SQ units) induced more pronounced IgG1, IgG2 and IgG4 responses to Bet v 1 and Bet v 1-related allergens according to the degree of sequence homology (Bet v 1>Aln g 1>Cor a 1>Mal d 1) than short-term SCIT (<1 year; cumulative dose <1,000,000 SQ units). In contrast to patients treated for <1 year, patients treated for >1 year mounted distinct IgG1, IgG2 and IgG4 responses against sequential Bet v 1 epitopes. No relevant allergen-specific IgA or IgG3 responses were induced by short- or long-term SCIT. Using a competitive ELISA assay, it could be shown that serum IgG from patients undergoing long-term SCIT inhibited IgE reactivity to Bet v 1 better than IgG from patients undergoing short-term SCIT. CONCLUSION: SCIT with allergen extracts adsorbed onto aluminum hydroxide induces IgG responses against new epitopes that block IgE binding and cross-react with structurally related allergens depending, among other factors, on duration of treatment and cumulative injected dose.

Absence of contact sensitization to Aloe vera (L.) Burm. f.

Aloe vera has been used as a cosmetic and medical remedy since ancient times and has gained increasing popularity in recent years. Despite its widespread use, reports of allergic reactions are rare. We patch tested 702 consecutive patients with an oily extract from the leaves, Aloe pulvis from the entire plant and concentrated Aloe vera gel. A specially designed questionnaire was used for the use of Aloe vera, reasons and location of application, adverse reactions, occupation, hobbies and atopy. None of the subjects showed any reaction to one of the preparations. 2 components of the plant have to be distinguished: the bark of the leaves contains anthrachinones with pro-peristaltic and potential antibiotic and anticancer properties. Constraints have been imposed due to their considerable toxic potential. Today, mostly the Aloe gel from the center of the leaves is processed. It almost exclusively consists of carbohydrates to which also many medical effects have been attributed. Carbohydrates are not likely to induce contact sensitization, which might explain the outcome of our study. However, this does not justify unrestrained promotion of Aloe products, as scientific studies investigating the claims on its constitutional effects are few in number, and the majority of them have been unable to diminish the intuitive scepticism against miracle cures, like Aloe seems to be.

The seamy side of natural medicines: contact sensitization to arnica (Arnica montana L.) and marigold (Calendula officinalis L.).

Medical remedies of plant origin have gained increasing popularity in recent years. Both anaphylactic and eczematous allergic reactions are on the rise, accordingly. Arnica and marigold, both of the Compositae family, are in widespread use, but only limited data are available on their allergenic potential. We tested 443 consecutive patients, in addition to the European standard and other series, with Compositae mix, sesquiterpene lactone mix, arnica, marigold, and propolis. 5 subjects ( approximately 1.13%) reacted to arnica, 9 ( approximately 2.03%) to marigold. The Compositae mix was positive in 18 cases ( approximately 4.06%). Among them were 3 out of 5 individuals with a sensitization to arnica, and 4 out of 9 who reacted to marigold. Sensitization to arnica and marigold was often accompanied by reactions to nickel, Myroxylon Pereirae resin, fragrance mix, propolis, and colophonium. We conclude that Compositae allergy contributes significantly to the epidemiology of contact dermatitis and that sensitization to arnica and marigold cannot be assessed by testing with the Compositae or sesquiterpene mix alone. As extracts of these plants are frequently used in occupational and cosmetic products, patch testing with additional plant extracts or adjustment of the commercial Compositae mix to regional conditions is recommended.

Delayed-type hypersensitivity and cross-reactivity to heparins and danaparoid: a prospective study.

BACKGROUND: Delayed-type hypersensitivity (DTH) reactions in patients receiving heparin may occur with both unfractionated (UFHs) and low molecular weight heparins (LMWHs). Skin testing is a clue to detect tolerated heparin or heparinoid preparations for further treatment. OBJECTIVE: To study in vivo cross-reactivity between LMWHs, UFHs, and danaparoid by skin testing in patients with suspected DTH to heparin. METHODS: Patients who fulfilled the criteria for the diagnosis of suspected heparin allergy were involved in a prospective study after informed consent. Patients presented with or had a history of typical erythematous plaques at the heparin injection sites. Skin testing was performed by subcutaneous injections of heparin (300-500 IU anti-Xa activity) and danaparoid (375 IU, eight patients). Desirudin (27,000 IU) was tested in three patients. We read skin reactions after 24, 48, and 96 hours and after 7 days. RESULTS: Fourteen female and 4 male patients were included in our series. Erythematous plaques had been reported or developed after 14-35 days in patients during first-time heparin treatment and after 2-10 days in reexposed patients. Positive skin test results were seen in 15 of 18 (83.3%) patients. Of these, 11 (73.3%) showed cross-reactivity between heparins and/or danaparoid. Six patients reacted to LMWHs only, nine patients to both LMWHs and UFHs. Danaparoid was tolerated in six of eight patients; desirudin was tolerated in all three patients tested. CONCLUSIONS: DTH to heparins is characterized by considerable cross-reactivity between LMWHs, UFHs, and danaparoid. UFHs may be tolerated even if LMWHs are not. Subcutaneous testing of a panel of heparins, danaparoid, and desirudin (hirudin) is recommended to determine acceptable treatment options for patients allergic to specific heparins.