超敏反应2015英五班

Hypersensitivity GuangjieChenDept ofImmunologyandMicrobiology2015 TheBigBangTheory Hypersensitivity allergy Hypersensitivityisaninappropriateimmuneresponse whichisheightenedreactivitytoanantigen suchresponseleadtotissuedamage immunopathology ThevarioushypersensitivitystateswereclassifiedintoIthroughIVtypesbyGellandCoombs TypeI IIandIIIreactionsaremediatedbyantibodies whereastypeIVreactionsaremediatedbyTcells I TypeIhypersensitivity anaphylaxis Themajorcomponents 1 allergendrug chemicalinhalantallergen pollens Dustmitefoodallergens nuts seafood Planetree Castor oilplant Dustmite 2 IgEantibodyandIgEreceptor LevelsofIgEandatopicdiseases IgEandIgEreceptorsIgE Fc RI ITAM AntigenindirectlycrosslinksFc Ronmastcellsorbasophils 3 Cells Mastcell basophils Fc RIeosinophils expressFc RIafterstimulationofIL 5 MCP 3CrosslinkDegranulationReleaseofpreformedmediatorsandnewlyproducedmediators LightphotomicrographandElectronmicrographofMastcellactivation AbulK abbasetal CellularandMolecularImmunology 7thedition ElsevierSaunders 2 MechanismofTypeIhypersensitivity SensitizationphaseExcitationphaseEffectorphase 1 SensitizationphaseallergenenterthebodystimulateAg specificBcellsdifferentiatedtoplasmacellsproductionofIgEBindwithhigh affinityFc RIwhichexpressedbymastcellsandbasophils Activatedmastcelloractivatedbasophil 2 ExcitationphaseThesameallergenenterthebodyagain bindtoIgEwhichwasboundtomastcellsand orbasophils crosslinkofFc RI inductionthedegranuationofmastcellsandbasophils releasebiologicalactivemediators Biologicalactivemediators 1 preformedmediators histamine eosinophilchemotacticfactor ECF kininogenase tryptase2 newlyproducedmediators leukotrienes prostaglandinD2 plateletactivatingfactor cytokines 3 EffectorphaseImmediatephase severalsecondsaftercontactofallergen canpersistseveralhours causedbyhistamineLatephase 6 12haftercontactofallergen canpersistseveraldays Distributionandfunctionofhistamine typeoftissueeffectclinicalreceptorcontractionrelaxationmanifestationH1airwaysmoothmuscles asthmaalimentarytractmuscles diarrhea vomitvascularendothelialcell edemaH2vascularsmoothmuscle shock AbulK abbasetal CellularandMolecularImmunology 7thedition ElsevierSaunders Biologiceffectsofmediatorsofimmediatehypersenitivity DifferentsubstancescrosslinkFc R 3 IgEmediatedallerigicdiseases typeIhypersensitivity 1 anaphylacticshockcausedbydrugs 2 anaphylacticshockcausedbyanimalserum TAT 3 hypersensitivityreactioninrespiratorytractallerigicrhinitis bronchialasthma 5 hypersensitivityreactioninskin 4 hypersensitivityreactioningastrointestinaltractseafood milk Beesting urticaria Allergicreactioninresponsetotestantigenscanbedividedintoanimmediateresponseandalate phaseresponse Asthmaticresponseinthelungswithnarrowingoftheairways PFER peakexpiratoryflowrate 4 PrincipalsofpreventionandtherapyfortypeIhypersensitivity 1 Skintest 2 DesensitizationtherapyHeteroserumdesensitization smalldose repeatedinjection 30 50mininterval TAT allergictopenicillinisforbiddentousethismethodSpecificallergendesensitization smalldose repeatedinjection longtimeinterval inducingIgGproduction decreasingIgEproduction 3 Drugtherapy Hygienehypothesis Theremarkableincreaseinasthmaprevalencethathasoccurredoverthelasttwodecadesisthoughttobecausedbychangesintheenvironmentduetoimprovedhygieneandfewerchildhoodinfection II TypeIIhypersensitivity cytotoxichypersensitivity MechanismoftypeIIhypersensitivity 1 AgcellsurfaceAg Ab IgG 2 specificAb complementandeffectorcellADCC CDC phagocytosis 2 CommondiseasescausedbytypeIIhypersensitivity 1 transfusionreactions BloodtypeAgAb serumAAanti BBBanti AABA BnoneOHanti A anti B 2 HemolyticdiseaseofthenewborninducedbyRhesusincompatibility 3 Autoimmunehemolyticanemiainfection changedepitopedrug hapten 4 Gravesdisease specialtype III TypeIIIhypersensitivity solubleimmunecomplex MechanismoftypeIIIhypersensitivitylargeimmunecomplexes phagocytosissmallimmunecomplexes kidneyfiltrationmedieumimmunecomplexes existforalongtime depositinsmallvessels 2 CommondiseasescausedbytypeIIIhypersensitivity 1 localimmunecomplex mediateddiseases1903ArthusArthusreaction arthus likereaction InhaledantigeninducedtypeIIIhypersensitivity Diseases antigen haydust farmer slung furprotein furrier slung pigeondroppings pigeon fancier sdisease Penicilliumcaseispores cheesewasher sdisease Hiddenmoldspores maplebarkstripper sdisease 2 Systemicimmunecomplex mediateddiseasesSerumsicknessPoststreptococcalglomerulonephritisRheumatoidarthritisSystemiclupuserythematosus Serumsickness IV TypeIVhypersensitivity cellmediated delayedtype 2 CommondiseasescausedbytypeIVhypersensitivity 1 InfectivehypersensitivityLeprosy Tuberculosis AbulK abbasetal CellularandMolecularImmunology 7thedition ElsevierSaunders Contactdermatitiscausedbyivyprison 2 Contactdermatitis AbulK abbasetal CellularandMolecularImmunology 7thedition ElsevierSaunders Example purifiedproteinderivative PPD aproteinAgofmycobacteriumtuberculosis elicitsaDTHreaction calledtuberculinreaction Positiveskintestresponseisclinicalindicatorforevidenceofpreviousoractivetuberculosisinfection Keypoints DefinitionofhypersensitivityreactionsMechanismofhypersensitivityreactionoffourtypesRelateddiseases EssayDiscussONEofthefollowingstatements Hygienehypothesis Theremarkableincreaseinasthmaprevalencethathasoccurredoverthelasttwodecadesisthoughttobecausedbychangesintheenvironmentduetoimprovedhygieneandfewerchildhoodinfection Allergicdiseases includingrhinitisandasthma arechronicinflammatorydisorderswithaprevailingTh2immuneresponse Theinhalationofallergensleadstohyperreactivity recruitmentofeosinophils mastcells andlymphocytesintheupperandlowerairwaystriggeringtheinflammatorycas