hüpersensitiivsust

Hüpersensitiivsus, also known as hypersensitivity, refers to an exaggerated or inappropriate immune response to an antigen. This response can be harmful to the body, leading to various allergic and autoimmune conditions. The immune system, which normally protects the body from pathogens, mistakenly identifies harmless substances as threats. These substances can be external, such as pollen, food particles, or medications, or internal, such as the body's own tissues.

There are four main types of hypersensitivity reactions, classified by Gell and Coombs. Type I hypersensitivity, often called immediate hypersensitivity or allergy, involves IgE antibodies and rapid onset symptoms like hives, asthma, or anaphylaxis. Type II hypersensitivity involves IgG or IgM antibodies attacking cells or tissues, leading to conditions like autoimmune hemolytic anemia. Type III hypersensitivity occurs when immune complexes form and deposit in tissues, causing inflammation, as seen in serum sickness or lupus. Type IV hypersensitivity, or delayed-type hypersensitivity, is cell-mediated, involving T cells and taking days to develop, such as in contact dermatitis or the tuberculin skin test. Understanding the specific type of hypersensitivity is crucial for diagnosis and treatment.