Interleukin-8/Neutrophil-ActivatingPeptide-1selectivelystimulatestheABIlityofneutrophilsandT-lymphocytestoinvadeinjuredorinflamedtissue.IL-8purifiedfromperipheralbloodmonocytesisa10kDaproteinshowingatleast4variantformswhichdifferinthelengthoftheN-terminalandreADIlyformdimersinsolution.Twocystin-bridgesareessentialfortheBIOLOGicalactivityofIL-8.IL-8exertsitseffectsviaspecificcellmembranereceptors(chemotacticagoNISTreceptor-family)withhomogeneoushigh-affinityactivityandtwobindingsitesforitsligand.Besidesitschemotacticinfluence,IL-8exertsotherdistinctcharacteristics.Inneutrophilsittriggersthesecretionofsuperoxideanionsandlysosomalenzymes,therebyindirectlyaugmentingthepermeabilityofbloodvessels,andIL-8enhancesthefungicidalactivityagainstCandidaalbicans.Neutrophilsaremorereadilyliberatedfromthebonemarrowreservoirundertheinfluenceofthiscytokine.Invitro,IL-8stimulatesarapidMac-1aswellasCR1,p150,95andLFA-1expressiononneutrophilswhichenablestheadherencetoactivatedvascularendothelialcellsexpressinge.g.ICAM-1.Otherfindingssuggestthatendothelial-derivedIL-8mayfunctiontoattenuateinflammatoryeventsattheinterfacebetweenvesselwallandblood,viainhibitingneutrophiladhesiontocytokine-activatedendothelialmonolayers.Thereforethesecellsseemtobeprotectedagainstneutrophil-mediateddamage.Inbasophils,besidesitschemotacticeffects,IL-8stimulatesthehistaminliberationinatopicaswellashealthypersons.ThepropertyofIL-8tostimulatemovementofneutrophilsacrossendothelialmonolayersinvitrosupportstheconceptofacentralroleforthismoleculeintheaccumulationofneutrophilsatinflammatorylesionsinvivo.DataindicatethatIL-8mayparticipateinthepathogenesisofrheumatoidarthritisviatheinductionofneutrophil-mediatedcartilagedamage,andpsoriasis.AcausativeinvolvementofIL-8isfoundwithinabroadrangeofclinico-pathologicalconditions:adultrespiratorydistresssyndrome,asthma,bacterialinfections,bladdercancer,bloodincomptability,contactdermatitis,empyema,graftrejection,glomerulonephritis,gout,haemolyticuremicsyndrome,immunevasculitis,inflammatoryboweldisease,influenzavirusinfection,Jarisch-Herxheimerreaction,malignanciesofthecentralnervoussystem,myocardialinfarction,placentalinfection,sepsis,uveitis,amongothers.DuetothenowadaysknownbiologicalpropertiesofIL-8,thiscytokine,especiallyincombinationswithotherneutrophilactivatingagents,mayprovehelpfulinthetreatmentofpatientssufferingfromgranulocytopenia,severeinfectionsagainstwhichantibioticsarenoteffective,andimmunodeficiencycausedbyHI-virus.

Synonyms:Monocyte-derivedneutrophilchemotacticfactor(MDNCF),T-cellchemotacticfactor,Neutrophil-activatingprotein1(NAP-1),Protein3-10C,Granulocytechemotacticprotein1(GCP-1),Monocyte-derivedneutrophil-activatingpeptide(MONAP),Emoctakin,Lymphocyte-derivedneutrophilactivatingfactor(LYNAP)