TypeIVhypersensitivityFromWikipedia,thefreeencyclopediaJumptonavigationJumptosearchMedicalconditionTypeIVhypersensitivityOthernamesDelayedtypehypersensitivitySpecialtyImmunology TypeIVhypersensitivityisoftencalleddelayedtypehypersensitivityasthereactiontakesseveraldaystodevelop.[1]Unliketheothertypes,itisnotantibody-mediatedbutratherisatypeofcell-mediatedresponse.ThisresponseinvolvestheinteractionofT-cells,monocytes,andmacrophages.ThisreactioniscausedwhenCD4+Th1helperTcellsrecognizeforeignantigeninacomplexwiththeMHCclassIIonthesurfaceofantigen-presentingcells.ThesecanbemacrophagesthatsecreteIL-12,whichstimulatestheproliferationoffurtherCD4+Th1cells.CD4+TcellssecreteIL-2andinterferongamma(IFN-γ),inducingthefurtherreleaseofotherTh1cytokines,thusmediatingtheimmuneresponse.ActivatedCD8+Tcellsdestroytargetcellsoncontact,whereasactivatedmacrophagesproducehydrolyticenzymesand,onpresentationwithcertainintracellularpathogens,transformintomultinucleatedgiantcells.TheoverreactionofthehelperTcellsandoverproductionofcytokinesdamagetissues,causeinflammation,andcelldeath.TypeIVhypersensitivitycanusuallyberesolvedwithtopicalcorticosteroidsandtriggeravoidance.[1]Contents1Forms2Seealso3References4ExternallinksForms[edit]Thissectionneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingcitationstoreliablesources.Unsourcedmaterialmaybechallengedandremoved.(May2017)(Learnhowandwhentoremovethistemplatemessage)DiseaseTargetantigenEffectsAllergiccontactdermatitis[2]Environmentalchemicals,likeurushiol(frompoisonivyandpoisonoak),metals(e.g.nickel),topicalmedicationepidermalnecrosis,inflammation,skinrash,andblistersAutoimmunemyocarditis[2]MyosinheavychainproteinCardiomyopathyDiabetesmellitustype1[2]Pancreaticbetacellproteins(possiblyinsulin,glutamatedecarboxylase)Insulitis,betacelldestructionGranulomas[3]Various,dependingonunderlyingdiseaseWalledofflesioncontainingmacrophagesandothercellsSomeperipheralneuropathiesSchwanncellantigenNeuritis,paralysisHashimoto'sthyroiditis[