Exam 2 Flashcards
classification of hyper sensitivity reactions
source of antigen, time (immediate or delayed), immunological mechanism causing tissue injury
types 1 2 and 3 sensitivities are
immediate, humoral immunity, and mediated by antibodies
type 4 sensitivity is
delayed, cell mediated immunity, and are mediated by T-cells and don’t involve antibodies
type 1 immune responce
IgE mediated reaction, from exposure to allergen, person becomes sensitized to allergen, IgE attaches to mast cells and basophils (chemical mediators of inflammation are released on second exposure), plasma cells produce the antibodies
type 1 reactions local
skin wheal localized (pale w/ fluid surrounded by reddened area) ex. mosquito bite
type 1 reactions systemic
anaphylaxis, occurs in minutes, can lead to airway obstruction and vascular collapse, initial itching and edema at site of exposure
manifestations of anaphylaxis
watery red eyes, bronchial edema (wheezing), dilated pupils, weak thread pulse, angioedema, cyanosis (first in finger tips and lips) shortness of breath
treatment of anaphylaxis
epinephrine, diphenhydramine (Benadryl), hydrocortisone, O2, IV fluids, H2 receptor blocker
type 1 atopic reactions
inherited tendency to become sensitized to environmental allergens, ex. allergic rhinitis asthma urticaria (hives) angioedema, atopic dermatitis
allergic rhinitis
hay fever, can be year round (dust mold animal dander), can be seasonal (pollen from grass weeds or trees), affects the eyes and respiratory tract (rhinorrhea= runny nose, lacrimation, mucosal swelling w/ airway obstruction, pruritus= itching)
atopic dermatitis
chronic skin disorder, increase IgE levels, skin lesions more generalized then wheal, blood vessels dilate and cause tissue edema
urticaria
cutaneous reaction to allergens, wheals (pink raised edematous pruritic), vary in shape/size, spread over body, after exposure to allergen, may last minutes or hours, hives
angioedema
localized skin lesions, like hives but deeper, effects eyelids lips tongue larynx hands/feet GI tract and genitalia
lab tests for type 1
eosinophil level elevated, eosinophils in sputum nasal and bronchial secretions, elevated IgE levels, ELISA test for IgE antibodies to allergens when skin cant be tested
type 2 immune response (examples and categories)
cytotoxic (cell toxic) and cytolytic (cell breakdown), Examples: hemolytic transfusion reaction, goodpasture syndrome, immune thrombocytopenic purpura, graves disease, RH incompatibility reaction, autoimmune and drug related hemolytic anemia
type 2 reactions (how it works)
tissue specific IgG/ IgM mediated, immunoglobulins attach to antigen on cell surface, mistakenly identifies normal cell as foreign and destroys target cell (normally WBC RBC or platelets), this antigen-antibody complex activates the complement system (results in cytolysis or phagocytosis)
type A blood is compatible with
type A or O
type B blood is compatible with
type B or O
type AB blood is compatible with
type A, B, AB, or O
type O blood is compatible with
only type O
Type O is the
universal donor
Type AB is the
Universal recipient
Incompatibility reaction (acute hemolytic reaction)
antibodies coat the foreign blood cells causing agglutination, this causes small blood vessels to be blocked which uses up clotting factors which can cause bleeding, within hours neutrophils and macrophages phagocytize the clumped cells
hemolytic transfusion reactions
as the cell dies it releases hemoglobin into the urine and plasma