HYPERSENSITIVITY REACTIONS Innocous materials can cause hypersensitivity in certain individuals unwanted inflammation damaged cells and tissues

ANTIBODY MEDIATED HYPERSENSITIVITY REACTIONS IgE Mast cell IgG FcγR+ cells NK, macrophage IgG – immune complex FcγR+ cells Complement Hay fever Asthma Systemic anaphylaxis Certain drug allergies (penicillin) Serum sickness

TYPE I HYPERSENSITIVITY REACTION ALLERGY

MAST CELL RESPONSE TO SURFACE FcRεI CROSSLINKING EARLY MEDIATORS Biogenic amins – histamin Enzymes – triptase, chymase, carboxypeptidase LATE MEDIATORS

allergic response Th2 B cell Th2 DC ALLERGENS USUALLY ENTER THE BODY VIA MUCOSAL SURFACES AND THEY ARE PRESENT AT A LOW DOSE antigen presentation T cell priming and polarization  soluble proteins on te surface of small particles (pollen, dust mite „drops”)  small molecular weight  trans-mucosal entry, enzymatic activity  low dose (ragweed: 1µg/year)

A Der p1 hasítja az okkludint A Der p1 –t felveszik a DC-k, Th2-priming A Der p1-specifikus IgE a hízósejtekhez kötődik A légutak intakt epitéliuma Der p1 The enzymatic activity of some allergens enables penetration of epithelial barriers

(LTB4, PGE2)

Copyright ©2005 American Society for Clinical Investigation

IMMUNE RESPONSES MEDIATED BY Th2 CELLS Bas IL-4 IL-13 ALLERGEN mucosal membranes

Mechanism of the initiation of Th2 response Immunology and Cell Biology (2008) 86, 637–638

chromosome 11q FcεRβ chain gene chromosome 11q IL-3-5 IL-9, IL-13 GMCSF HLAII DRB1*015 allergy Inproper immunregulation Th1/Th2 inbalance regulation of IgE synthesis high eosinophil counts Environmental factors lack of tolerance GENETIC/ENVIRONMENTAL PREDISPOSITION TO ALLERGY Genetic factors

Treatment

Types of IgE-derived allergic response SYNDROME ALLERGENSROUTE OF ENTRYRESPONSE systemic anaphylaxis drugs anti-serum peanuts intravenous Per os edema, increased vascular permeability tracheal occlusion circulatory collapse, death acute urticaria bug bite allergy test subcutanlocal increase in blood flow and vascular permeability allergic rhynitis pollen dust mite drops inhaledirritation and edema of nasal mucosa airway inflammation asthmaanimal fur pollen dust mite drops inhaledbronchial constriction, increased mucus production food allergynut, peanuts, fish, shellfish milk, eggs Per osvomiting, diarrhea pruritis (itching) urticaria (hives) anaphylaxia (rare)