Hipersensitivitas Tipe 1 (Immediate Hypersensitivity), Immunology

Summary

This video script from the YouTube channel 'Formatio Es Halus' delves into the topic of hypersensitivity, a condition where the immune system overreacts to certain stimuli. It explains that hypersensitivity can be triggered by foreign antigens like bacteria or viruses, or by self-antigens leading to autoimmune diseases. The script focuses on Type 1 hypersensitivity, also known as immediate hypersensitivity, which is mediated by Immunoglobulin E (IgE) and can lead to allergies. It details the process from allergen exposure to the activation of mast cells and the release of inflammatory mediators like histamine, which can cause symptoms such as difficulty breathing in asthma or skin reactions like hives. The video also touches on treatments for hypersensitivity reactions, including antihistamines, corticosteroids, and leukotriene modifiers, and emphasizes the importance of prompt medical attention for severe systemic reactions like anaphylaxis.

Takeaways

• 🧬 Hypersensitivity is an overreaction of the immune system that can damage cells and tissues and potentially trigger autoimmune diseases.
• 🌐 Hypersensitivity can be triggered by two conditions: foreign antigens like bacteria, viruses, and other substances, or self-antigens from within the body like red blood cells and proteins.
• 🔍 Hypersensitivity is categorized into four types: Type 1 (Immediate Hypersensitivity), Type 2 (Antibody Mediated), Type 3 (Immune Complex Mediated), and Type 4 (Cell Mediated).
• 🚨 Type 1 Hypersensitivity, also known as Immediate Hypersensitivity, occurs quickly, within minutes of exposure to an antigen.
• 🛡 Immunoglobulin E (IgE) mediates Type 1 Hypersensitivity, binding to allergens and effector cells, leading to allergic reactions.
• 🍎 Common allergens include food, medication, dust, mold, and pollen, which can cause conditions like asthma.
• 🌪 In the case of asthma, allergens enter the respiratory tract and are captured by dendritic cells, leading to the activation of T-cells and the production of cytokines.
• 🤧 Histamine, a key mediator released during an allergic reaction, binds to H1 receptors causing bronchoconstriction and other symptoms like edema and hives.
• 💊 Medications such as antihistamines (e.g., cetirizine), corticosteroids (e.g., methylprednisolone), and leukotriene modifiers (e.g., montelukast) can manage allergic reactions.
• 🚑 Severe systemic reactions like anaphylaxis require immediate medical attention and can be treated with epinephrine injections.

Q & A

What is hypersensitivity?

Hypersensitivity is an overactive immune response that is not desired because it can destroy cells and tissues, and even trigger autoimmune diseases in patients.

What are the two conditions that can trigger hypersensitivity?

Hypersensitivity can be triggered by foreign antigens such as bacteria, viruses, pollen, and other foreign substances, or by self-antigens like red blood cells and various proteins within the body.

How does the immune system's failure to tolerate self-antigens lead to disease?

The failure of the immune system to recognize self-antigens leads to a condition known as autoimmune disease.

What are the four types of hypersensitivity?

The four types of hypersensitivity are Type 1 (Immediate hypersensitivity), Type 2 (Antibody-mediated), Type 3 (Immune complex-mediated), and Type 4 (Cell-mediated).

What is Type 1 hypersensitivity and what is its characteristic reaction time?

Type 1 hypersensitivity, also known as immediate hypersensitivity, is characterized by a rapid reaction that can occur within minutes after exposure to an antigen.

Which immunoglobulin mediates Type 1 hypersensitivity?

Type 1 hypersensitivity is mediated by Immunoglobulin E (IgE).

How does the immune system respond to allergens in Type 1 hypersensitivity?

In Type 1 hypersensitivity, dendritic cells capture allergens and present them to naïve T cells, leading to the differentiation of T-helper 2 cells, which produce cytokines that bind to B cells, resulting in the production of IgE antibodies.

What is the role of histamine in allergic reactions?

Histamine, released during an allergic reaction, binds to H1 receptors around the respiratory tract, causing smooth muscles around the bronchi to constrict, leading to difficulty in breathing.

What are some common allergens that can trigger Type 1 hypersensitivity?

Common allergens that can trigger Type 1 hypersensitivity include certain foods, medications, dust, and pollen.

What are the two types of reactions that can occur in Type 1 hypersensitivity?

The two types of reactions in Type 1 hypersensitivity are local reactions, such as allergic rhinitis, and systemic reactions, such as anaphylactic shock.

What are some medications that can be used to treat allergic reactions?

Medications used to treat allergic reactions include antihistamines like cetirizine, corticosteroids like methylprednisolone and dexamethasone, and leukotriene antagonists like montelukast.