Alterations in Immunity - Patho Fall 2022

Alterations in Immunity - Patho Fall 2022 allergy exaggerated immune response against environmental antigen - Produces deleterious effects to environmental (exogenous) antigens Autoimmunity misdirected response against the host's own cells -A disturbance in immunologic tolerance of self antigens - CAN CAUSE autoimmune diseases lupus erythematosus an autoimmune disorder characterized by a red, scaly rash on the face and upper trunk most common in women Alloimmunity directed against beneficial foreign tissue immune system reaction against antigens on the tissues of other members of the same species EX: Think of transfusions and transplants Transient neonatal alloimmunity: fetus expressing parental antigens not found in the mother, mom sensitized against the fetus EX: transplant rejection and transfusion reaction Can also be called isoimmunity Transfusion Reactions Occur if mismatched blood is infused Two major carbohydrate antigens: Are A and B co-dominant. Individuals have antibodies to the A and B antigens they lack. Anti-A and anti-B antibody production are induced by similar antigens on naturally occurring bacteria in the intestinal tract. Antibodies are usually of the IgM class (isohemagglutinins). O blood type: Is a universal donor. AB blood type: Is a universal recipient Ex: If patient A neg receives O pos blood, will see lysis & clumping of RBC's transfusion reaction •Is primarily expressed on erythrocytes. •Rh-positive: Expresses the D antigen on the RhD protein. •Rh-negative: Does not express the D antigen. •Approximately 15% of North American white individuals are Rh-negative. •Rh-negative individuals can make anti-D if exposed to Rh-positive erythrocytes •Hemolytic disease of the newborn: Rh-negative mother gives birth to a Rh-positive infant immunodeficiency insufficient response to protect the host - all responses can be serious or life threatening allergy, autoimmunity, alloimmunity 3 types of hypersensitivity reactions: Hypersensitivity