IMMUNOLOGY

Detailed explanation-1: -Type I hypersensitivity is also known as an immediate reaction and involves immunoglobulin E (IgE) mediated release of antibodies against the soluble antigen. This results in mast cell degranulation and release of histamine and other inflammatory mediators.

Detailed explanation-2: -Immediate hypersensitivity reactions are mediated by IgE, and T and B cells play important roles in the development of these antibodies.

Detailed explanation-3: -Within the allergic inflammation activated mast cell synthesizes prostaglandin D2 (first lipid mediator) which has bronchoconstrictive and vasodilating effects and attracts neutrophilic leukocytes. Moreover, it also participates in the late phase reactions, six hours subsequent to the exposure to the allergen.

Detailed explanation-4: -Cellular destruction. Phagocytosis (by neutrophils or macrophages), antibody-dependent cell-mediated cytotoxicity (ADCC), and formation of membrane attack complex (MAC) are the primary mechanisms of cell death. Inflammation. Cellular dysfunction.