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Melisa Hinijosa
MELISA (Memory Lymphocyte Immunostimulation Assay) is a blood test that detects type IV hypersensitivity to metals, chemicals, environmental toxins and molds. Type IV hypersensitivity reactions, particularly to nickel, are well established and may affect 20% of the population.Silverberg N, Pelletier J, Jacob S, Schneider L. Nickel allergic contact dermatitis: identification, treatment, and prevention. Pediatrics 2020; 145. https://doi.org/10.1542/peds.2020-0628. Mechanism The MELISA test measures type-IV delayed hypersensitivity reaction. Type-IV reactions are mediated by T-lymphocyte, T-lymphocytes (or memory lymphocytes) that have had prior contact with a given allergen.Stejskal V, Forsbeck M, Nilsson R. Lymphocyte transformation test for diagnosis of isothiazolinone allergy in man. J Invest Dermatol 1990; 94: 798–802. This is in contrast to a type-I allergy, which is mediated by IgE Antibody, antibodies and is often tested using an ELISA test. In genetically predisposed indiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type IV Hypersensitivity
Type IV hypersensitivity, often called delayed-type hypersensitivity, is a type of hypersensitivity reaction that can take a day or more to develop. Unlike the other types, it is not humoral (not antibody-mediated) but rather is a type of cell-mediated response. This response involves the interaction of T cells, monocytes, and macrophages. This reaction is caused when CD4+ Th1 cells recognize foreign antigen in a complex with the MHC class II on the surface of antigen-presenting cells. These can be macrophages that secrete IL-12, which stimulates the proliferation of further CD4+ Th1 cells. CD4+ T cells secrete IL-2 and interferon gamma (IFNγ), inducing the further release of other Th1 cytokines, thus mediating the immune response. Activated CD8+ T cells destroy target cells on contact, whereas activated macrophages produce hydrolytic enzymes and, on presentation with certain intracellular pathogens, transform into multinucleated giant cells. The ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |