Immunodeficiency Pathophysiology for nurses (University of Maryland) Hypersensitivity and Immunodeficiency N2100

Disorders of Immune Responses • Most immune reactions are positive: attack organisms or mutated cells; mediate healing • Immune disorders include – Hypersensitivity and allergy – Transplant immunopathology/rejection – Autoimmune diseases – Immune deficiency oaded_by Hypersensitivity • Altered immunologic reaction to an antigen • A state of altered reactivity→ an exaggerated immune response to what is perceived as a foreign or harmful oaded_by Hypersensitivity Types • Allergy: immune response to environmental antigen (allergen) • Autoimmunity – Reactions to self antigens – Neoantigens d/t medications • Alloimmunity – Reactions to antigens on transplanted oaded_by Hypersensitivity Categories • Classified by source – Allergy, autoimmune, alloimmune • Classified by mechanism of reaction – Type I: IgE mediated – Type II: Tissue Specific • (antibody mediated) – Type III: Immune complex mediated – Type IV: Cell mediated • (T lymphocytes)oaded_by Type I: IgE Mediated • Includes most “allergic reactions” – Excessive reactions to foreign antigens that are inhaled, ingested, contact, etc. – Pollens, molds, fungi, animal dander, foods • Type I reactions – Can begin rapidly – Range from annoying to life-threatening • Immune components involved: – TH2, IgE, Mast Cells, Boaded_by Type I • Th cells recognize allergen • Plasma cells produce IgE antibody to allergen • Mast cell sensitization – IgE antibodies attach to receptors on mast cells/ basophils • Subsequent Exposure – Antigen attaches to antibodies on the mast cell or basophil – Mast cells activated • Histamine and chemotactic factor • Prostaglandin and oaded_by Type I Roaded_by Two phase reaction • Primary (early) response within 5 to 30 minutes – Release of histamine, chemotactic factors from mast cells • Secondary (late) response: 2 to 8 hours later – Arachidonic acid pathway→ prostaglandins and leukotrienes – Leukocyte and eosinophil infiltration