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Immunologically Mediated Diseases and Allergic Reactions
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Kim A. Campbell, Caroline C. Whitacre
Allergies to certain foods, dust, or animal dander can be controlled by avoidance of the allergen. However, ubiquitous allergens such as ragweed, grasses, or certain tree pollens are difficult to avoid. Many allergy patients undergo allergen immunotherapy, which is a technique that involves subcutaneous injection of increasing doses of an allergen over a period of weeks or months in hopes of reducing allergen-specific IgE levels. Allergen immunotherapy has proven successful for treatment of allergic asthma and rhinitis, but the mechanism by which this treatment improves clinical symptoms is not entirely clear. Following repeated injections of allergen, there is an increase in antigen-specific IgG antibodies, which are postulated to function by neutralizing antigen, by blocking the interaction of antigen and IgE, and by negatively regulating IgE production through antibody feedback mechanisms. Desensi tiza ti on through continued allergen injection could also downregulate IgE production by shifting the predominance of antigen-specific TH2 T lymphocytes to TH1 cells or by inducing specific T cell tolerance.
Common Office Tests and Procedures for the Allergist
Published in Pudupakkam K Vedanthan, Harold S Nelson, Shripad N Agashe, PA Mahesh, Rohit Katial, Textbook of Allergy for the Clinician, 2021
Allergen immunotherapy is a cornerstone of the allergist’s practice. The focus here will be on subcutaneous allergen immunotherapy. Although an increasing number of studies have demonstrated the efficacy of sublingual immunotherapy (SLIT), FDA-approved products are limited to only three antigens: dust mite, grass pollen and ragweed. Therefore, SLIT will not be discussed. Similarly, oral immunotherapy (OIT) for food allergy is considered investigational at this juncture, and will not be discussed either.
Asthma
Published in James M. Rippe, Lifestyle Medicine, 2019
David E. Ciccolella, Gilbert E. D’Alonzo
Allergen immunotherapy can be helpful in certain allergic asthmatic patients.2,27,28 According to the NAEPP Expert Panel Report 3, subcutaneous immunotherapy can be considered for patients who have prominent allergies, as with allergic rhinoconjunctivitis, and who have mild to moderate persistent asthma (steps 2 to 4).2,13 However, it is preferable to have clear evidence of a relationship between asthma symptoms and exposure to the allergen in question. Finally, symptoms should be nearly perennial and difficult to control with pharmacotherapy alone. The whole concept of allergen immunotherapy is under constant debate, in terms of long-term benefit. If allergen immunotherapy is s tarted, it should be given under the careful guidance of a well-trained immunotherapist who is capable of treating any life-threatening reaction that may occur.29 The immunotherapy should be directed at a single or only a very few antigens. There is a paucity of data support for use of multiple-allergen mixes. The responses to therapy may be specific to the allergen extracts and regimens used and it has been recommended to use those allergen extracts shown to have efficacy in clinical trials.13 Finally, the optimal duration of allergen therapy is not clear but typically is three to five years, and a recognizable favorable improvement in asthma should occur early in treatment.
Presentation, diagnosis, and the role of subcutaneous and sublingual immunotherapy in the management of ocular allergy
Published in Clinical and Experimental Optometry, 2021
Amruta Trivedi, Constance Katelaris
The general proposed mechanism of action of allergen immunotherapy and induction of immune tolerance is shown in Figure 3. Immunotherapy or desensitisation leads to induction of regulatory T cells, which release interleukin‐10 and transforming growth factor beta, which then cause early suppression of mast cells, basophils, and eosinophils, thereby reducing release of their pro‐inflammatory mediators following aeroallergen exposure. Interleukin‐10 and transforming growth factor beta also suppress T‐helper‐2 cells, which are critically involved in allergic diseases, and also suppress inflammatory dendritic cells, while inducing tolerogenic dendritic cells. Finally, interleukin‐10 and transforming growth factor beta promote immunoglobulin class switching, by promoting production of IgG4 and IgA, which compete with IgE for allergen binding, thereby limiting the IgE mediated activation and degranulation of mast cells and basophils that cause the allergic response.
Chronic rhinosinusitis: pathogenesis, therapy options, and more
Published in Expert Opinion on Pharmacotherapy, 2018
Umut Can Kucuksezer, Cevdet Ozdemir, Mubeccel Akdis, Cezmi A. Akdis
Th2 predominance and nasal mucosal inflammation mainly caused by the increased recruitment of eosinophils are marked findings observed in AR. It is evident that, in patients with AR, nasal mucosal inflammation may influence the predisposition to CRS [80]. Thus, it may be reasonable to accept that AR treatment may also improve CRS outcomes [81]. Recently, the combined use of azelastine hydrochloride and fluticasone propionate as MP29-02 was reported to reduce the levels of inflammatory mediators and nasal hyperreactivity in patients with AR, thereby restoring nasal epithelial barrier function [82]. In addition to pharmacotherapy, the two other best-known strategies in the management of allergic diseases are avoidance measures for the responsible allergen and allergen immunotherapy (AIT) [83]. AIT is a unique and effective therapy option for allergic disorders, as it pursues the underlying mechanisms and possibly alters the disease course through the induction of long-lasting allergen tolerance. Few studies have evaluated the effectiveness of AIT in atopic CRS patients, including both CRSwNP and CRSsNP patients. A systematic review focusing on the role of AIT in CRS reported that in non-randomized controlled trials, the symptom scores in patients receiving AIT were improved compared with those at the baseline and those of the control patients. It also commented on the lack of available data on the efficacy of AIT for CRS-specific treatment outcome measures when used as an adjunct to conventional therapies [84].
New pharmaceutical approaches for the treatment of food allergies
Published in Expert Opinion on Drug Delivery, 2018
Ana Brotons-Canto, Nekane Martín-Arbella, Carlos Gamazo, Juan M. Irache
In summary, FA, defined as an adverse immune response to food proteins, affect to an increased percentage of population. Currently, management of FA consists of educating the patient to avoid ingesting the responsible allergen and initiating therapy if accidentally this ingestion occurs. In the last years, novel therapeutic approaches have been proposed including allergen-specific immunotherapies (oral, sublingual, or cutaneous administration) and immunomodulatory treatments (e.g. monoclonal antibodies, probiotics, etc.). Allergen immunotherapy involves the administration of daily small amounts of an allergen over long periods of time (up to some years), that compromise the adherence of patients to the treatments. In addition, these immunotherapy treatments would not offer adequate tolerogenic immune responses. In order to solve these drawbacks, the association of allergens with nanoparticulate adjuvants would be an adequate approach to develop more effective and safer treatments. Thus, nanoparticles can be designed to reach the gut epithelium and, taken into account their inherent inclination to be naturally captured by APCs, facilitate the development of tolerance by promoting strong and lasted Th1 responses. On the other hand, immunomodulatory treatments based on monoclonal antibodies have been proposed in order to block the allergic response. Nevertheless, in spite of the significant progress developed in the last years, there is still much to be done to offer these new approaches to FA patients.