Allergic Rhinitis Hypersensitivity type-I Fadel Muhammad GarishahFaculty of Medicine Universitas Diponegoro Review on Clinical Immunology
Clinical Case A 10 years old boy came to the Physicianwith his mother, complaining about hisendless-influenza-like illness in the summer.The boy has to stay in his Granny’s houseduring the summer, and that diseases alwayscome. He gets better when he comes home. His Granny’s house is located near byflower-garden as his Grandfather is a gardenerand flowers distributor.
Clinical symptoms • Sneezing and flu-like illness when contact with the allergen • Mucosal edema • Redness • Hypersecretion of mucus
Introduction• Rhinitis is an inflammation of the nasal mucous layer• Allergic rhinitis/hay fever is initiated by hypersensitivity reactions to one of a large group of allergens, most commonly plant pollen, fungi, animal allergens and dust mites.• Affects 20% US Population• IgE mediated (early- and late-phase) immediate hypersensitivity (type I)
Classification• Seasonal allergic rhinitis (SAR): happening at the same time each year, (Spring/Summer where pollen spreaded all the air)• Perrenial allergic rhinitis (PAR): happening everytime in a year, (mainly caused by dust, animal allergen, fungi, cockroach)• Occupational allergic rhinitis: related to occupation
Immunopathology I1. Sensitization• Allergen bind to B-Cell as APC, transformed into Plasma cell secreting IgE• IgE bind to FcεRI of Mast cell/Basophils.• This will be a memory- fuction to allergen• Th2 Mediated the spreading of allergen introduction.
Immunopathology II2. Allergic Response• Repeat exposure to allergen• Activation of mast cells/basophils in large number in nasal mucosa.• Degranulation and releasing many allergic- response mediators
Effects of AllergicResponse in Rhinitis • Vasoactive amines. The most important mast cell–derived amine is histamine. Histamine causes intense smooth muscle contraction, increased vascular permeability, and increased mucus secretion by nasal
• Histamine, PAF, Leukotrienes C4, D4, E4 Neutral proteases that activate complement and kinins, Prostaglandin D2 : Vasodilation, increased vascular permeability• Edema of the nasal mucous• Redness around the nose, the mediator of inflammatory cause itchy• Increasing of mucous secret worse the breathing• Stimulation of the sneezing mechanism repeatedly by p-substances? Neuropeptides?