The current definition of an immediate hypersensitivity reaction (IHSR) involves anaphylactic type clinical manifestations that occur within the first one (to ...ResearchTopicTheRoleofMastCellsinImmediateHypersensitivityReactionsSubmissionclosed.OverviewArticlesAuthorsImpactViewsAboutthisResearchTopicThecurrentdefinitionofanimmediatehypersensitivityreaction(IHSR)involvesanaphylactictypeclinicalmanifestationsthatoccurwithinthefirstone(tosix)hour(s)afterexposuretoatrigger.Themostcommontriggersthatcaninduceimmediatereactionsaredrugs,food,venomandlatex.The...Thecurrentdefinitionofanimmediatehypersensitivityreaction(IHSR)involvesanaphylactictypeclinicalmanifestationsthatoccurwithinthefirstone(tosix)hour(s)afterexposuretoatrigger.Themostcommontriggersthatcaninduceimmediatereactionsaredrugs,food,venomandlatex.ThepathophysiologyofIHSRinvolvestheactivationanddegranulationofmastcellsandbasophils.Thosecellsreleasemediators,suchashistamine,lipidmetabolytes,cytokinesandproteases.Thisleadstovasodilation,increasedvascularpermeabilityandsmoothmusclecontraction.Bothmastcellsandbasophilscanbeactivatedbyimmunologicalandnon-immunologicalmechanisms.MastcellsarecomponentsoftheinnateimmunesystemandareconsideredthemajoreffectorcellsofIHSRs.ImmunologicalIHSRs,(alsonamedtypeIhypersensitivityreactions),areantigenspecificandIgEmediated.Mastcellsareactivatedthroughexposuretoanallergenthatcross-linksallergen-specificIgE,ifthisisalreadyboundtothehigh-affinityFcepsilonreceptor1(FcεRI)onthecellsurface.Alternatively,mastcellscanbeactivatedanddegranulatedafternon-specific(non-immunological)mechanisms,includinganaphylatoxins(C3aandC5a),physicalstimuli(pressureandtemperaturechanges),infections,cytokinesandneuropeptides.Moreover,mastcellscanbeactivatedafterinhibitionofcyclooxygenase-1bynonsteroidalanti-inflammatorydrugs(NSAIDs),thataremajortriggersofurticaria,angioedemaandanaphylaxis.Furthermore,anovelmechanismwasrecentlydescribedtoexplainsomenonallergicanaphylacticreactions.Cationicsubstances,actingasb