ABSTRACT

Inanefforttoclarifytheseconflicts,mylaboratoryhasreassessedlymphocytesubsetsin asymptomaticseropositiveblooddonors(mostlyHTLV-11).Incontrasttoourearlierstudythat utilizedaSpectrumIIIflowcytometer(OrthoDiagnostics,Westwood,MA)(239),thisstudy utilizedaFACScanflowcytometer(BectonDickinsonImmunocytometrySystems,SanJose, CA),whichofferssuperiorsensitivityfordetectingdimfluorescence(240).Wealsoemployed anewlyavailablemonoclonalantibodydefiningmemoryTcells,CD45RO(66).Thismarker definesapopulationsimilar,butnotidentical,tothepopulationdefinedbyCD29expression. TheresultsaresummarizedinTableS.Insupportofourpreviousfindings,thepercentagesof T,CD4,CDS,andBcellswerenormalintheHTLVgroup;likewise,theCD45RA+CD4

population was unchanged. We also found that the percentage of CD45RO+CD4 cells was unchanged in the HTLV group. In contrast to our previous findings, however, the percentage of DR+CDS cells was significantly increased in the HTLV group; further, the percentage of DR +CD4 cells was subtly but significantly increased. The identification of an increased percentage of DR +CDS cells was directly attributable to improved fluorescence detection by the F ACScan; the specimens with increased DR+ CDS values on the F ACScan gave normal values when analyzed on the Spectrum III (e.g., a sample with 11% DR +CDS cells using the FACScan gave only 4% DR +CDS cells using the Spectrum III). Thus, differences in instrumentation may partially explain the conflicting data in the literature for certain subset changes in HTL V infection.