ICAM-1=intercellularadhesionmolecule-1;MPI=minimalpersistentinflammation.Availableonlinehttp://respiratory-research.com/content/2/6/320IntroductionTheoverallviewofthepathophysiologyofrespiratoryallergyhaschangedprofoundlyoverthepast10years.Increasingattentionhasbeendevotedtotherelationshipbetweenrhinitisandasthma(i.e.betweentheupperandthelowerrespiratoryairways)thatwasfirstnotedinepi-demiologicalstudies.Inaddition,clinicalobservationsprovidecompellingevidenceforthefollowingphenomena:thefrequentco-existenceofrhinitisandasthma,rhinitisasariskfactorfordevelopingasthma,theoccurrenceofbronchialhyperresponsivenessinrhinitis,theassociationbetweenupperrespiratoryinfectionsandasthmaexacerba-tions,theexistenceofacommonpathogenicmechanismsbetweenrhinitisandasthma,andtheexacerbatingroleofsinusitisinasthma.Moredetailedknowledgeofthemecha-nismsofinflammation(e.g.antigenpresentation,cytokines,chemokinesandadhesionmolecules)hasclarified,atleastinpart,thefunctionalrelationshipsbetweenthenoseandbronchi.Itisthereforereasonabletoconsiderrespiratoryallergyasadisorderofthewholerespiratorytract,whichismanifestclinicallyasrhinitisand/orasthma,ratherthanasdistinctdiseasesconfinedtospecificorgans.Conse-quently,somenewtermshavebeenintroduced,including‘allergicrhinobronchitis’,‘oneairwayonedisease’,and‘unitedairwaysdisease’[1].Thisapproachofconsideringrespiratoryallergyasadisorderofthewholerespiratorytracthasrelevanttherapeuticimplicationsbecausetreatingdiseasesoftheupperairwayscanimpactthelowerairways,anddrugsaffectingthecommonpathogenicmechanismscanactonbothcompartments.FunctionalandimmunologicalaspectsTheassociationbetweentheupperandlowerrespiratoryairwayshasbeenconfirmedbynumerousepidemiologicalCommentaryImpactofrhinitisonairwayinflammation:biologicalandtherapeuticimplicationsGiovanniPassalacquaandGiorgioWalterCanonicaAllergyandRespiratoryDiseases,DepartmentofInternalMedicine,UniversityofGenoa,ItalyCorrespondence:GiovanniPassalacqua,MD,Allergy&RespiratoryDiseases—DepartmentofInternalMedicine,Pad.Maragliano,L.goR.Benzi10,Genoa16132,Italy.Tel:+390103538908;fax:+390103538904;e-mail:gcanonica@qubisoft.itAbstractThereisincreasingevidenceforacloselinkbetweentheupperandthelowerrespiratorytractsandthefactthatrhinitishasanimportantimpactonasthma.Severalclinicalandexperimentalobservationssuggestasimilarimmunopathologybetweentheupperandlowerairwaysinallergicsubjects..Thecommoninflammatoryprocessthatdevelopsintherespiratorytractexplainssomeofthecomplexinteractionsamongdifferentclinicaldiseasessuchasrhinitis,sinusitis,asthma,bronchialhyper-responsivenessandviralinfections.Therearealsonon-inflammatorymechanismsthatmaycontributetothelinkbetweenrhinitisandasthma.Moreover,theoutcomesofvariouspharmacologicaltreatmentsofrhinitishaverecentlyprovidedfurthersupportforthehypothesisoftheunitedairways.Wediscusssomeoftherecentobservationsonthenose–lunginteractionandsomeofthenoveltherapeuticapproachesusedtotreatrhinitisandasthmathatarisefromthis.Keywords:asthma,inflammation,rhinitis,sinusitis,unitedairwaysReceived:9May2001Revisionsrequested:26June2001Revisionsreceived:23July2001Accepted:25July2001Published:13September2001RespirRes2001,2:320-323Thisarticlemaycontainsupplementarydatawhichcanonlybefoundonlineathttp://respiratory-research.com/content/2/6/320©2001BioMedCentralLtd(PrintISSN1465-9921;OnlineISSN1465-99...