Impaired cytotoxicity associated with defective na

ImpairedcytotoxicityassociatedwithdefectivenaturalkillercelldifferentiationinmyelodysplasticsyndromesbyMaryamHejazi,AngelaR.Manser,JuliaFröbel,AndreaKündgen,XiaoyiZhao,KathrinSchönberg,UlrichGerming,RainerHaas,NorbertGattermann,andMarkusUhrbergHaematologica2015[Epubaheadofprint]Citation:HejaziM,ManserAR,FröbelJ,KündgenA,ZhaoX,SchönbergK,GermingU,HaasR,GattermannN,andUhrbergM.Impairedcytotoxicityassociatedwithdefectivenaturalkillercelldifferentia-tioninmyelodysplasticsyndromes.Haematologica.2015;100:xxxdoi:10.3324/haematol.2014.118679Publisher'sDisclaimer.E-publishingaheadofprintisincreasinglyimportantfortherapiddisseminationofscience.Haematologicais,therefore,E-publishingPDFfilesofanearlyversionofmanuscriptsthathavecompletedaregularpeerreviewandhavebeenacceptedforpublication.E-publishingofthisPDFfilehasbeenapprovedbytheauthors.AfterhavingE-publishedAheadofPrint,manuscriptswillthenundergotechnicalandEnglishediting,typesetting,proofcorrectionandbepresentedfortheauthors'finalapproval;thefinalversionofthemanuscriptwillthenappearinprintonaregularissueofthejournal.Alllegaldisclaimersthatapplytothejournalalsopertaintothisproductionprocess.Copyright2015FerrataStortiFoundation.PublishedAheadofPrintonFebruary14,2015,asdoi:10.3324/haematol.2014.118679.ImpairedcytotoxicityassociatedwithdefectivenaturalkillercelldifferentiationinmyelodysplasticsyndromesRunninghead:NKcelldeficiencyinMDSMaryamHejazi1,AngelaR.Manser1,JuliaFröbel2,AndreaKündgen2,XiaoyiZhao1,KathrinSchönberg1,UlrichGerming2,RainerHaas2,NorbertGattermann2,andMarkusUhrberg11InstituteforTransplantationDiagnosticsandCellTherapeutics,Heinrich-HeineUniversityDüsseldorf,MedicalFaculty,Germany2DepartmentofHematology,OncologyandClinicalImmunology,Heinrich-HeineUniversityDüsseldorf,MedicalFaculty,GermanyCorrespondingAuthor:MarkusUhrberg,PhDInstituteforTransplantationDiagnosticsandCellTherapeutics(ITZ),Heinrich-HeineUniversityDüsseldorf,MedicalFacultyMoorenstr.5D-40225DüsseldorfPhone:[phone]Fax:[phone]e-mail:[e-mail]2AbstractNaturalKillercellsarewellknowntomediateanti-leukemicresponsesinmyeloidleukemiabuttheirroleinmyelodysplasticsyndromesisnotwellunderstood.Here,inacohortofnewlydiagnosedpatients(n=75),widespreadstructuralandfunctionalnaturalkillercelldefectswereidentified.Firstly,onesubgroupofpatients(13%)hadaselectivedeficiencyofperipheralnaturalkillercells(count10/mm3blood)withnormalfrequenciesofTandnaturalkiller-likeTcells.Naturalkillercell-deficientpatientswerepredominantlyfoundinhigh-risksubgroupsandweresignificantlyassociatedwithpoorprognosis.Inthesecondsubgroup,representingthemajorityofpatients(76%),naturalkillercellswerepresentbutexhibitedpoorcytotoxicity.ThedefectwasstronglyassociatedwithreducedlevelsofperforinandgranzymeB.Notably,naturalkillercellfunctionandarmingofcytotoxicgranulescouldbefullyreconstitutedbyinvitrostimulation.FurtherphenotypicanalysisofthesepatientsrevealedanimmaturenaturalkillercellcompartmentthatwasbiasedtowardsCD56brightcells.TheresidualCD56dimcellsexhibitedasignificantincreaseoftheunlicensedNKG2A-KIR-subsetandastrikingreductionincomplexityoftheKIRrepertoire.Takentogether,theseresultssuggeststhatthewidespreaddefectsinnaturalkillercellfunctionofmyelodysplasticpatientsaremostlyduetoeitherunsuccessfulorinefficientgenerationofmature,functionallycompetentnaturalkillercells,whichmightcontributetodiseaseprogressionduetoimpairedimmunesurveillance.IntroductionMyelodysplasticsyndromes(MDS)constituteaheterogeneousgroupofbonemarrowdisorders,whicharecharacterizedbydysfunctionalhematopoieticprogenitorcellsandapropensityofevolutiontoacutemyeloidleukemia(AML).1AccordingtotheWHOclassificationsystem,differentMDSsubgroupsaredistinguishedbasedonthedegreeofdysplasia,thefrequencyofringsideroblasts,andthenumberofmedullaryand/orperipheralblasts.2Whilethemajorityofpatientsisinitiallydiagnosedwithlow-gradedisease,approximatelytwothirdsofpatientseventuallysuccumbtomulti-lineagecytopeniaortransformationtoleukemia.3Theriskoftumorprogressioncanbeestimatedbytheinternationalprognosticscoringsystem(IPSS),classifyingpatientsintofourgroups(low,intermediate1and2,orhighrisk)basedoncytogenetic,morphological,andclinicalcriteria.4TheetiologyandpathophysiologyofMDS,whichisthemostcommonhematopoieticmalignancyoftheelderly(age70y),remainincompletelydefined.TheroleofimmunologicaldeterminantsinMDSarepoorlyunderstood.Itisknownthatasubgroupofpatientsrespondstoimmunosuppressivetreatment.However,immunosuppressioncouldcompromiseproperimmunesurveillanceforaberranthematopoieticprogenitorcellsandfavorexpansionofthemalignantclone.5Inthisregard,theroleofnaturalkiller(NK)cellsisofrisinginterest.NKcellscanexertgraft-versus-leukemiaresponsesaspreviouslyshowninthesettingofhaploidenticalstemcelltransplantationforacutemyeloidleukemia.6NKcellfunctionisdeterminedbyabalanceofstimulatoryandinhibitoryreceptorssurveyingtheorganismforsignsofviralinfections,cellularstress,andmalignanttransformation.Tothisend,NKcellsexpressavarietyofstimulatoryreceptorssuchas