Patho- Immune Disorders- Type I Hypersensitivity (Exam 4)

What type of sensitivity is an allergic or atopy reaction?

• I

• II

• III

• IV

What is the mechanism of a type I hypersensitivity?

• Ag induces cross-linking of IgE bound to mast cells and basophils with release of vasoactive dilators

• Ab directed against cell surface antigens mediates cell destruction via complement activation or Ab-dependent cell-mediated cytotoxicity (ADCC). RBCs are common targets

• Ag-Ab complexes deposited in various tissues induce complement activation an dan ensuing inflammatory response mediated by massive infiltration of neutrophils

• sensitized T cells (TH1, TH2, and others) release cytokines that activate macrophages or TC cells, which mediate direct cellular damage

What are the typical manifestations of a type I hypersensitivity?

• Induce systemic anaphylaxis and localized anaphylaxis such as hay fever, asthma, hives, food allergies, and eczema

• includes blood transfusion reactions, erythroblastosis, fettles, and autoimmune hemolytic anemia

• includes localized Arthus reaction and generalized reactions such as serum sickness, necrotizing vasculitis, glomerulonephritis, RA, and systemic lupus erythematosus

• includes contact dermatitis, tubular lesions, and graft rejection

What are the signs and symptoms of allergic rhinitis?

• sneezing (and sneezing so hard/frequently that you get infraorbital cyanosis)

• nasal, ocular, palatal itching (which can cause the occurrence of transverse nasal crease)

• runny nose and/or congestion

• pale, bluish nasal mucosa

• cough

What are the laboratory findings of allergic rhinitis?

• nasal eosinophils

• evidence of allergen-specific IgE by skin or radioallergosorbent testing (RAST)

• topical skin rash

• extranasal fluid

Which immunoglobulin is responsible for type I hypersensitivity?

• IgE

• IgG

• IgA

• IgM

In a person who is not experiencing a type I hypersensitivity or infection with worms, is the concentration of IgE high or low in concentration in the blood serum?

• high

• low

What two things initiate an allergy?

• IgE antibody

• multivalent antigen

• T cells

• memory B cells

_________ individuals produce IgE against common environmental antigens.

• atopic

• allergic

• weak

When atopic individuals produce IgE against common environmental antigens, what are the antigens usually?

• proteins

• glycoproteins

• pet dander

• environmental factors (pollen etc)