11 February 2020 The true name of the anti-allergic vaccine is specific allergen immunotherapy , also known by the acronym SIT . SIT is currently the only medical intervention that potentially change the natural course of allergic disease . To better understand what this means, you must understand what the allergic response is. What is immunotherapy? Specific allergen immunotherapy is a medical procedure in which increasing amounts of a specific allergen are administered regularly to an allergic patient so that their immune system learns to tolerate it . How does immunotherapy work? Immunotherapy stimulates a population of lymphocytes, called regulatory T cells . These cells can balance the immune response leading to the tolerance of a specific allergen. Immunotherapy not only effectively relieves allergy symptoms , but has a long-term effect after treatment is completed, preventing the progression of allergic diseases. Which patients should have SIT and how is it done? Specific allergen immunotherapy should be considered in patients with evidence of having specific IgE antibodies to clinically relevant allergens. Currently, in clinical practice, immunotherapy can be administered subcutaneously (under the skin) or sublingually (under the tongue). Most airborne allergens (aeroallergens), such as pollens and mites, can be administered by any of the above routes. Hymenopteran poisons (wasp and bee) can only be administered subcutaneously. Can SIT be done at home? When a substance to which a patient is allergic is administered, adverse reactions may occur . In sublingual administration , the dose is very small, and the risk of reaction is minimal. Thus, in this case, treatment can be done at home . In subcutaneous administration , the dose is higher and the risk of reaction increases. As such, treatment should always be carried out under medical supervision . What results can be expected from SIT? After specific allergen immunotherapy, which usually lasts between 3 and 5 years, the following results are expected to be achieved: symptoms decrease; disease control improvement; decreased risk of disease progression; decreased need for medication; prevention of new sensitizations; quality of life improvement; decrease of direct and indirect costs related to the disease. The authors of this text are the following allergologists from the Hospital da Luz network: Luís Miguel Borrego, Ana Morais Mendes, Ana Reis Ferreira, Andreia Ferrão, Carlos Braga, Cristina Lopes, Diana Pereira da Silva, Filipa Semedo, Isabel Costa Silva, João Gaspar Marques, Pedro Carreiro Martins, Marta Salgado, Nuno Sousa, Rosa Anita Fernandes, Susana Piedade The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
