Hypersensitivity Reactions and Methods of Detection

Hypersensitivity reactions are classified into four groups (Type I, II, III, and IV), each characterized by specific biological actions. Research has focused on understanding each hypersensitvity to ensure appropriate therapeutic recommendations are made. This overview will present the defining characteristics of each hypersensitivity and examine the diagnostic methods used to determine the existence of a specific type. Type I hypersensitivities can be determined by provacation testing, immediate-type skin testing, or radioallergosorbent tests (RASTs); Type II hypersensitivities can be determined by measuring the level of IgG antibodies to specific host proteins; Type III hypersensitivities may be detected with serum IgG antibody testing to specific antigens; Type IV hypersensitivities are determined by delayed skin testing or memory lymphocyte immunostimulation assay (MELISA). Persistent antigen exposure may contribute to chronic conditions such as autoimmune diseases, irritable bowel syndrome, asthma, or even psychiatric illnesses. Through the effective detection of potential hypersensitivities, a patient’s quality of life can be improved through consequent antigen avoidance.