Coombs and Gell's classification divides allergies into four pathophysiological types, namely the immediate (type I), cytotoxic (type II), ...SkipmainnavigationAllnewsFutureLearnLocalPressInsightsHowToHome/Healthcare&Medicine/Allergies:WhentheImmuneSystemBackfires/CoombsandGellclassificationLearnmoreaboutthiscourse.CoombsandGellclassificationInthisarticleAndreasJ.BircherintroducesthewidelyknownclassificationofallergicreactionsaccordingtoCoombsandGell.©UniversityofBaselIn1963,twoBritishimmunologists,RobertCoombsandPhilipGell,publishedinabookanewschemeforclassifyingdifferenttypesofhypersensitivityreactions.Althoughknowledgeontheunderlyingimmunologicalprocesseshasgreatlyexpandedoverthepast50years,thissimpleclassificationisstillusednowadays.CoombsandGell’sclassificationdividesallergiesintofourpathophysiologicaltypes,namelytheimmediate(typeI),cytotoxic(typeII),immunecomplex-mediated(typeIII),anddelayedhypersensitivity(typeIV)reactions.Thedifferentpathophysiologicalmechanismsleadtovaryinglatencyperiodsforthefourclasses:typeIallergicsymptomsalreadyappearafterafewsecondstominutes;symptomsoftypeIIreactionsappearafterminutestohours;signsoftypeIIIallergicreactionssetinafterseveralhours;andfinally,fortypeIVreactions,alonglatencyofhourstodaysisexpected.TypesItoIIIarealsotermed‘humoral’reactions,becausethesearemediatedbysolublefactors(ieantibodies),whereasintypeIV,primarilycells(ieTcells)areinvolved.Whilethethreehumoraltypeshaveremainedbasicallythesameoverthepast50years,forthecell-mediatedtypeIVreaction,furthersubclassificationshavebeenproposed.PleasehavealookatthePDFattachedtothisarticlenow.Thereyou’llfindatablesummarizingtheCoombsandGellclassification,includingcommonallergens,latencies,mediators,effectormechanisms,andtheclinicalsignsofeachtype.ImmediatetypeIallergiesaremostcommonand,forthisreason,intheactivitiesofWeek2we’llmainlyfocusonthisclass.Youmightwanttohavealookattheallergens,theeffectormechanisms,andtheclinicalsignsofthistypeandcomparethesetothecharacteristicsoftheremai