ToinvestigatetheimbalancestateofhelperTlymphocytes(Th)andcytotoxicTlympho-cytes(Tc)andtherolesofTh1/Th2/Th3andTc1/Tc2cellsinrenaltransplantationrejection,theper-centagesofthesecellsinperipheralbloodof24casesofrenaltransplantationrecipientswithacutere-jectionandthedynamicchangesoftheCD4/CD8ratioweredeterminedbyflowcytometryanalysis,while30casesofhealthyinpidualsweresetupascontrols.Inthesehealthycontrols,thepercentagesoftheTh1,Th2andTh3cellswere(10.45±8.15)%,(5.05±4.15)%and(3.90±3.21)%,andthoseofTc1andTc2cellswere(9.83±7.03)%and(4.51±2.17)%,respectively.However,thepercentagesofTh1andTclcellsinperipheralbloodofthestablerecipientsaftertransplantationwere(7.29±5.62)%and(7.04±5.15)%,showingdefinitereduction,whilethoseofTh2,Th3andTc2cellsshowedsignificantincrease,(6.34±5.67)%,(4.94±4.14)%and(6.86±4.42)%,respectively.Incaseofrecipientswithacuterejection,thepercentagesofTh1andTc1cellsappearedtobe(18.55±13.21)%and(15.84±11.72)%,alsoshowingsignificantincrease,butthoseofTh2,Th3andTc2cellsappearedtobereduced,(4.19±3.62)%,(3.02±2.83)%and(3.88±1.63)%,respectively.Significantdifferencescouldbedetectedamongthesethreegroups(P<0.05).TheCD4/CD8ratioincaseswithacuterejectionwashigherthanthoseofstablerecipients(2.24±0.59vs1.95±0.45),butthatofthestablerecipientsandhealthycontrols(1.98±0.31)showednoanysignificantdifference.Fromtheaboveobservation,itisevidentthatimbalancebetweenTh1,Th2andTh3withTc1andTc2cellsmayexistafterrenaltransplantationandprobably,theim-muneimbalancemaybeinducedthroughthesecretionofcytokinesINF-γbyTh1orTc1cells,Ⅱ-4byTh2andTc2cellsandTGF-βbyTh3.