ABSTRACT

Figure1isacompositerepresentationoftypicalchangesinCD4andCD8celllevels, includingthoseintheprimaryinfectionstage,foranindividualwhodevelopedAIDS4.5years afterHIVinfection(56,57).Immediatelyafterinfectionbutpriortothedevelopmentofprimary symptomsandantibodiestoHIV,CD4andCD8levelsarenormal.Soonaftertheseroconversion illnessbegins(usuallyaroundday9),thereisadrasticdropinthetotallymphocytecount resultingindramaticdecreasesintheabsolutenumbersofCD4andCD8cells;therelative percentagesofCD4andCD8cellsdonotdecreaseduringthisphage,however.Aroundday 16ofillness,thetotallymphocytecountrebounds;bythispoint,however,theCD8cellnumber isslightlygreaterthantheCD4cellnumber,anditissignificantlyelevatedcomparedwith preillnessvalues.Duringthenextphaseofillness,theCD4cellnumberincreasesslightly, whereastheCD8cellnumberskyrockets;theCD8cellnumberusuallypeaksaround1month afterthebeginningofseroconversionillness.Thelastphaseoftheprimaryillnessis characterizedbygradualstabilizationofCD4andCD8cellnumbersoverthenext2-3months; bythistime,theCD8cellcounthastypicallystabilizedatabout1000cells/j..Ll,andtheCD4 counthasstabilizedatabout600cells/~J.l.Overthenext2-3years,CD4celllevelsslowly decreaseandCD8celllevelsincreasesomewhat.Approximately18monthsbeforethe developmentofAIDS,theCD4cellcountbeginsapercipitousdecrease,fallingatamuch

CD4

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