Delayed Hypersensitivity Reactions | Type 4 hypersensitivity
ForYouNews&PerspectiveDrugs&DiseasesCME&EducationAcademyVideoDecisionPointEdition:ENGLISHDEUTSCHESPAÑOLFRANÇAISPORTUGUÊSLogInSignUpIt'sFree!Edition:ENGLISHDEUTSCHESPAÑOLFRANÇAISPORTUGUÊSRegisterLogInNoResultsNoResultsForYouNews&PerspectiveDrugs&DiseasesCME&EducationAcademyVideoDecisionPointclosePleaseconfirmthatyouwouldliketologoutofMedscape.Ifyoulogout,youwillberequiredtoenteryourusernameandpasswordthenexttimeyouvisit.LogoutCancelhttps://profreg.medscape.com/px/getpracticeprofile.do?method=getProfessionalProfile&urlCache=aHR0cDovL2VtZWRpY2luZS5tZWRzY2FwZS5jb20vYXJ0aWNsZS8xMzYxMTgtb3ZlcnZpZXc=processing....Drugs&Diseases>Allergy&ImmunologyDelayedHypersensitivityReactionsUpdated:May07,2018Author:StuartLAbramson,MD,PhD;ChiefEditor:MichaelAKaliner,MD more...ShareEmailPrintFeedbackCloseFacebookTwitterLinkedInGoogle+SectionsDelayedHypersensitivityReactionsSectionsDelayedHypersensitivityReactionsOverviewBackgroundPathophysiologyEpidemiologyShowAllPresentationHistoryPhysicalCausesShowAllWorkupLaboratoryStudiesImagingStudiesOtherTestsProceduresHistologicFindingsShowAllTreatmentMedicalCareConsultationsShowAllMedicationMedicationSummaryCorticosteroidsShowAllFollow-upDeterrence/PreventionComplicationsPrognosisPatientEducationShowAllReferencesOverviewBackgroundDelayedhypersensitivityreactionsareinflammatoryreactionsinitiatedbymononuclearleukocytes.Thetermdelayedisusedtodifferentiateasecondarycellularresponse,whichappears48-72hoursafterantigenexposure,fromanimmediatehypersensitivityresponse,whichgenerallyappearswithin12minutesofanantigenchallenge.ThesereactionsaremediatedbyTcellsandmonocytes/macrophagesratherthanbyantibodies.TheyarealsotermedtypeIVhypersensitivityreactions.Delayedhypersensitivityisamajormechanismofdefenseagainstvariousintracellularpathogens,includingmycobacteria,fungi,andcertainparasites,anditoccursintransplantrejectionandtumorimmunity.ThecentralroleofCD4+TcellsindelayedhypersensitivityisillustratedinpatientswithAIDS.BecauseofthelossofCD4+cells,thehostresponseag
常見健康問答
Tuberculin hypersensitivityUrticaria type 4 hypersensitivityType 2 hypersensitivityGell and Coombs classificationType 4 hypersensitivityType 2 type 3 hypersensitivityDelayed-type hypersensitivityHypersensitivity type