T cells in Human Disease
Our immune system plays a crucial role in protecting our body against pathogens, but sometimes there is an exaggerated response. This exaggerated response is triggered by the interaction of the immune system with an antigen (allergen) and is referred to as hypersensitivity . Hypersensitivity is believed to be the cause of allergy and some auto-immune disease . In this article, we will discuss mainly Type IV Hypersensitivity . Classification Immunoreactants Clinical Presentation Type I Mast cell mediated, IgE dependent (anaphylactic, and IgE independent) Anaphylaxis, urticaria, angioedema, sthma , and hay fever Type IIa Antibody-mediated cytotoxic reactions (IgG and IgM antibodies complement often involved) Immune cytopenias Type IIb Antibody-mediated cell-stimulating reactions Graves disease and chronic idiopathic urticaria Type III Immune complex–mediated reactions complement involved Serum sickness and vasculitis Type IVa Th1...