Allergen specific immunotherapy by Yash.pptx

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1. Allergen specific immunotherapy By – Yash Guldagad

2. Allergen-Specific Immunotherapy (ASIT) Allergen-Specific Immunotherapy (ASIT) , also known as  desensitization  or  hyposensitization , is a long-term treatment for  allergic diseases  that aims to reduce sensitivity to specific allergens. It works by  modifying the immune system's response  to allergens, providing symptom relief and potentially preventing the progression of allergies.

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4. Indications ASIT is effective for  IgE-mediated allergic conditions , such as: Allergic Rhinitis (Hay Fever) Allergic Asthma Allergic Conjunctivitis Insect Venom Allergy  (e.g., bee or wasp stings) Mild Food Allergies  (experimental in some cases)

5. Mechanism of Action ASIT involves the  gradual administration of increasing doses  of the allergen to induce  immune tolerance . Over time, it shifts the immune response from a  Th2-dominated response  (which produces IgE) to a  Th1/T regulatory cell response . Key mechanisms include: Reduction of allergen-specific IgE  levels. Increase in allergen-specific IgG4 and IgA  (blocking antibodies). Inhibition of mast cell and basophil activation . Promotion of  T regulatory cells  ( Tregs ) that suppress allergic responses.

6. Types of Allergen-Specific Immunotherapy Subcutaneous Immunotherapy (SCIT) Administration : Injections under the skin, usually in the upper arm. Schedule : Build-up phase : Injections weekly for 3–6 months with increasing doses. Maintenance phase : Injections every 4–6 weeks for 3–5 years. Use case : Pollen, dust mites, animal dander, and venom allergies. Sublingual Immunotherapy (SLIT) Administration : Allergen tablets, drops, or oral dissolvable films placed under the tongue. Schedule : Daily administration for 3–5 years. Use case : Mostly used for pollen allergies (e.g., grass, ragweed) and dust mites.

7. . Oral Immunotherapy (OIT) Administration : Oral ingestion of small, gradually increasing doses of a specific food allergen (e.g., peanut or milk). Use case : Experimental for food allergies.

8. Advantages of ASIT Reduces  symptoms  and  medication requirements .Provides long-term benefits even after stopping therapy.Can prevent the  progression  of allergic rhinitis to asthma.Decreases the development of new  sensitivities .

9. Risks and Side Effects Local Reactions : Swelling, redness, or itching at the injection site (in SCIT). Systemic Reactions : Sneezing, hives, or asthma symptoms. Anaphylaxis : Rare but serious; more common with SCIT, requiring administration under medical supervision.SLIT has fewer risks but can cause mild  oral itching  or gastrointestinal symptoms.

10. Contraindications Uncontrolled asthma  (high risk of anaphylaxis). Autoimmune diseases  or  immunodeficiency . Pregnancy  (should not initiate therapy but can continue ongoing treatment). Beta-blocker therapy  (may interfere with treatment for anaphylaxis).

11. Monitoring and Follow-Up SCIT: Must be administered in a  clinical setting  with monitoring for  30 minutes  post-injection to detect early signs of anaphylaxis. SLIT: Can be taken at home after the first dose under medical supervision.

12. Effectiveness Improvement in  symptoms  and  quality of life  usually becomes noticeable within  6–12 months  of starting therapy. Full benefits are achieved after  3–5 years , with long-term tolerance in many patients.

13. Conclusion Allergen-specific immunotherapy is a well-established treatment for allergic conditions that modifies the immune system to develop  tolerance  to allergens. Though it requires long-term commitment, ASIT provides  lasting symptom relief  and may prevent the  progression of allergic diseases . It is especially beneficial for patients who do not respond well to conventional pharmacotherapy (e.g., antihistamines or corticosteroids).

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