Immunotherapy Of Allergic Diseases Research Articles

Investigation of different recombinant isoforms of grass group-V allergens (timothy grass pollen) isolated by low-stringency cDNA hybridization--antibody binding capacity and allergenic activity.

A cDNA library of timothy grass pollen was screened for homologous isoforms of major group-V allergens by low stringency hybridization with a Phl p 5 (Phleum pratense) probe. After restriction analysis of the 40 clones obtained, 17 were selected for cDNA sequencing. Of these clones, two were unrelated to group-V allergens, six showed high similarity but an incomplete open reading frame and nine had high similarity with a complete open reading frame. Comparison of deduced amino acids of ten complete cDNA clones confirmed the presence of two major isoforms, a and b. Within these two subgroups, only minor sequence variations were observed. Eight isoforms were expressed in Escherichia coli K12 and purified to homogeneity. Although the subgroups a and b could be distinguished by their molecular masses and by binding constants towards monoclonal antibodies, all isoforms turned out to be biochemically similar. Ribonuclease activity as a marker for the biological function of group-V allergens was shown to be in the same range for both subgroups. Analysis of allergenic B-cell responses towards the isoforms in 26 grass pollen allergic patients revealed that the IgE reactivities to the different isoforms were identical for each individual. IgE reactivities and allergenic activities of three isovariants and an allergen of a different group were compared in a selected group of four grass pollen allergic patients by immunoblot, histamine-release and skin-prick tests. The IgE reactivity does not necessarily mirror the allergenic activity of the single molecule, and the variability of allergenic activity between the isovariants does not, in every case, depend on the structural differences of these allergens. We conclude that group-V isoallergens in grass pollen, although they can be structurally different, induce a similar B-cell response but can show variable allergenic activity. Thus, the most allergenic isoform of each important group of allergens should be sufficient for the diagnosis of type-I allergy. Whether the isoallergenic variation has any significant influence on the outcome of immunotherapy in allergic disease still has to be elucidated.

New studies of immunotherapy in allergic disease

Researchers investigating the use of specific immunotherapy (SIT) to treat allergic diseases have conducted studies to confirm the long-term efficacy and tolerability of SIT and to identify the most effective route of SIT administration. The results of these studies were presented at the European Academy of Allergology and Clinical Immunology [Budapest, Hungary; June 1996].

What Is the Role of Immunotherapy in Allergic Diseases?

Immunotherapy is a controversial treatment for allergic diseases. However, controlled studies, either with a control group or as placebo-controlled double-blind trials, have documented a significant efficacy in Hymenoptera allergy, rhinitis and asthma. No strict scientific guidelines as to the use of immunotherapy can be provided. However, the 1993 Immunotherapy Position Paper of the European Academy of Allergology and Clinical Immunology recommended immunotherapy for patients with an unequivocal IgE-mediated disease who do not respond adequately to allergen avoidance and who require prophylactic topical corticosteroids for long periods. The clinical benefit, risk and potential preventive aspects of immunotherapy should be carefully assessed. Immunotherapy should as a routine only be initiated with allergens that have been shown in controlled studies to have clinical efficacy and safety. A treatment approach using immunotherapy as a supplement to pharmacotherapy is recommended, thereby interfering broadly with the pathophysiological mechanisms of allergic inflammation.

Modified par j I allergen from P. judaica pollen and its rate of absorption in rats

Polymerized allergens (allergoids) have been introduced in the immunotherapy of allergic disease in order to reduce the risk of side effects. However, their high molecular weight can be a limit, particularly when they are administered by a route involving passage through the mucosal barrier. We describe a simple procedure aimed at developing an original modified allergen with significantly less allergenic potential (intended as human IgE-binding capacity) but preserving the monomeric nature of the molecule. Par j I, the major allergen of Parietaria judaica pollen, was purified by a combination of monoclonal antibodies and affinity chromatography. Par j I allergen was then modified by reaction with potassium cyanate (KCNO), and compared with the native allergen to evaluate its allergenic potency (RAST-inhibition) and molecular weight (SDS-PAGE). Modified allergen showed significantly lower allergenic potency but kept its original molecular weight, making it particularly suitable for buccal (sublingual) administration. To study the adsorption profile, modified Par j I was radiolabeled and administered intravenously and sublingually to normal rats. The prospects for clinical application of the modified allergen are discussed.

Immunotherapy of allergic diseases.

Immunotherapy (IT) of IgE-mediated diseases has been used since its first description in 1911. This therapy has been used in patients with inhalant allergy and insect venom sensitivity. Unfortunately, IT suffers from the crudeness of the allergy extracts and the inability to define allergenic epitopes. Moreover, this form of IT has been increasingly questioned because of improvements in pharmacotherapy and the risks of untoward reactions. These untoward reactions even include anaphylaxis and death. Despite this criticism, there are increasing data on the efficacy of immunotherapy and considerable research is underway to improve the risk-benefit ratio of treatment. Other approaches directed at inhibiting the sequential events of both the afferent and efferent limbs of allergic reactions are in progress. This involves specific alterations of target cells, i.e., mast cells and basophils. Moreover, the development of recombinant allergens and the precise definition of the binding site of IgE will further promote research and development of new means of IT. Gene targeting therapy may follow, directed at T cells specific for allergen epitope(s) or IgE binding sites. The future holds great promise and excitement.

Environmental control and immunotherapy for allergic disease

Treatment for allergic disease can help prevent recurrent sinusitis. Removal of carpeting and feather bedding and use of acaricides can significantly improve symptoms caused by house dust mites or animal dander. To kill mites, wash-water temperature must be at least 58 ° C. Patients with severe allergy should use an air-filtering vacuum cleaner and an air cleaner with a HEPA filter. Humidity should be kept at under 50%. If other measures fail, pets may have to be removed. Subcutaneous immunotherapy is effective for patients with anaphylactic reactions to insect stings, allergic rhinitis, and allergic asthma. It is ineffective for food allergy or nonallergic rhinitis or asthma. In children, immunotherapy is reserved for generalized life-threatening airway reactions. Relative indications for immunotherapy include inability to avoid the allergen and poor results or significant side effects from pharmacologic treatment. Efficacy depends on dosage, duration of treatment, and allergen selection. Low initial doses are increased at a set rate until the dose induces appropriate antibody response without significant reactions. Patients should be much improved or symptom-free for 1 to 2 years before immunotherapy is discontinued. Pollen, house dust mite, cat, and some mold spore extracts reduce symptoms and sensitivity to nasal or bronchial provocation. When used appropriately, immunotherapy is safe and effective.

Liposomes as vehicle for allergen presentation in the immunotherapy of allergic diseases

Liposomes are non-toxic, biodegradable and weakly immunogenic lipid vesicles which can be used as immunomodulating agents. In the present study, multilamellar vesicles (MLV) and small unilamellar vesicles (SUV) were used to incorporate an allergenic protein from Artemisia scoparia pollen. MLV incorporated more allergenic protein than SUV. To assess the immunomodulating effect of allergen entrapped in liposomes, Swiss strain mice (made IgE responders) were injected with either free allergen or liposome-entrapped allergen (LEA) and their immune response was measured in terms of specific IgG and specific IgE levels. Results indicated that specific IgE response was significantly lower in mice injected LEA (P less than 0.02) than in mice injected free allergenic protein. Although specific IgG response was higher in mice injected LEA, there was no statistically significant difference between the two groups. Potential use of liposomes as non-immunogenic biocompatible vehicle for antigen presentation in immunotherapy will be discussed.

The role of IgG subclass antibodies in the clinical response to immunotherapy in allergic disease

The role of IgG subclass antibodies in the clinical response to immunotherapy in allergic disease

Production of multilamellar, small unilamellar and reverse-phase liposomes containing house dust mite allergens: Potential adjuvants in the immunotherapy of allergic disease

The capacity of multilamellar (MLV), small unilamellar (SUV) and reverse-phase vesicle (REV) liposomes to incorporate house dust mite allergens has been studied. All three liposome preparations entrapped mite proteins with efficiencies of 36% (SUV), 29% (MLV) and 14% (REV). MLV incorporated the complete range of proteins contained in mite extracts with apparent molecular weights ranging from 14 000 to > 67 000 as judged by sodium dodecyl sulphate polyacrylamide gel eletrophoresis. However, several proteins with apparent molecular weights (MW) of 16 000, 36 000 and 43 000 were excluded from the REV and SUV. Immunoblotting analysis using a serum pool prepared from mite allergic individuals showed that whereas the whole spectrum of allergens was incorporated into the MLV, a MW 43 000 allergen was excluded from the REV and SUV. The exclusion of these mite components is probably a function of the relatively prolonged exposure of the original extract to organic solvent in the preparation of the REV and SUV liposomes.

Immunotherapy of allergic diseases: a forthcoming therapy.

Immunotherapy of allergic diseases: a forthcoming therapy.

Immunotherapy for Allergic Diseases

The efficacy of immunotherapy is related to the dose administered, and the immune response is specific for the allergen injected. The larger dose will provide the higher level of IgG blocking antibody and will provide the most symptomatic relief of symptoms. Increased frequency of injections seems to stimulate production of blocking antibody. Much work is currently under way to provide modified forms of immunotherapy designed to elicit the immune response without the allergic or adverse reactions of the allergen. Polymerized antigens, allergoids and glutaraldehyde-treated tyrosine-absorbed allergens are examples of such modifications. It is quite possible that within a short time extracts will be available commercially such that a patient will be adequately immunized with only a very few injections. Hymenoptera venom immunotherapy offers virtually complete protection for those patients who in the past were at great risk from stings. Proper history, skin testing, extract prescribing, and extract administration all are vital points in the successful immunotherapy of a patient.

Immunotherapy of asthma

Immunotherapy of allergic diseases can be effective. The injection of allergen into the sensitized host induces a number of cellular and humoral changes associated with clinical improvement. Although studies demonstrating clear efficacy are available for immunotherapy for allergic rhinitis, additional information is needed for complete evaluation of immunotherapy in asthma.

Erste Ergebnisse �ber klinische Erfahrungen mit Conjuvac, einer lyophilisierten, spezifischen Immuntherapie allergischer Erkrankungen

The present state optimizing immunotherapy of allergic diseases is to reduce the allergenic parts in the vaccination to the most potent fractions. On the other hand an optimum on standardisation and stability of the therapy solutions should be reached. Dome-Miles-Hollister-Steer Laboratories developed a new substance, Conjuvac, an allergen-alginate conjugate of a dialysed extract of Dactylis glomerata and Phleum pratense which is biologically standardized and freeze dried after extraction to reach these aims. Together with six more European centres we had a clinical trial on 125 patients comparing the clinical efficacy and security of the new substance with a conventional treatment. Clinical efficacy based mainly on the correlations between the daily symptoms and the regional pollen expositions. Serological tests included the determination of grass specific IgE and IgG. There were no significant differences between the treatments in the different analyses after the first period of preseasonal specific immunotherapy. The results of the 2nd year are still based on the patients treated in Austria. A further increase of the specific IgG in all treatments and a slightly better clinical efficacy was seen in the Conjuvac group. Even after the 3rd treatment period, just finished, we do not note any difference according to side effects.