Quality control in the flow cytometric measurement of T-lymphocyte subsets: The Multicenter AIDS Cohort Study experience

Giorgi, Janis V.; Cheng, Hui Ling; Margolick, Joseph B.; Bauer, Kenneth D.; Ferbas, John; Waxdal, Myron J.; Schmid, Ingrid; Hultin, Lance E.; Jackson, Anne L.; Park, Larry; Taylor, Jeremy M. G.

doi:10.1016/0090-1229(90)90096-9

Cited by 245 publications

(114 citation statements)

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“…3). Secondly, lymphocyte counts show diurnal variations [48.49J and biood samples for CD4 counts need to be taken at a standard time ofthe day [49], From low values in the morning, lymphocyte absolute counts and CD4"^> values increase to peak values at 10 PM [49], The increment in CD4 absoiute counl can be as high as a cumulative 60%: from 082 X lO^/to l-32x 10'// (Table 4), In our study blood was regularly donated during the morning, as reflected in our low ranges (Table 4), In Ihe female control group, however, blood was mostly taken in the afternoon, and signiiicantly higher absolule CD4 counts were seen (I 05x 10'*//;TabIe2), The largest American multi-centre study also shows moderately higher absolute values [23], and these may be due in part to diurnal factors and/or minor differences in setting up leucocyte counting.…”

Section: Discussionmentioning

confidence: 90%

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Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis

Bofill

Jánossy

Lee

et al. 1992

Clinical and Experimental Immunology

196

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SUMMARYWith the advent of standard flow cytometric methods using two-colour fluorescence on satnpies of whole blood, it is possible to establish the ranges of CD3, CD4 and CD8 T lymphocyte subsets in the routine laboratory, and also to assist the definition of HIV-l-re!ated deviations from these normal values. In 676 HIV-I-seronegative individuals the lymphocyte subset percentages and absolute counts were determined. The samples taken mostly in the morning. The groups included heterosexual controls, people with various clotting disorders but without lymphocyte abnormalities as well as seronegative homosexual men as the appropriate controls for the HIV-I-infected groups. The stability of CD4"/ values was demonstrated throughout life, and in children CD4 values <25% could be regarded as abnormal. The absolute counts ofall Tcell subsetsdeereased from birth until the age of ID years. In adolescents and adults the absolute numbers {mean±s.d.) of lymphocytes, CD3. CD4 and CD8 eells were I 90 + 0-55. I 45 + 046. 083+029 and 056 + 0 23 X iO'*//, respectively. In patients with haemophilia A and B the mean values did not differ signifieantly. In homosexual men higher CD8 levels were seen compared with heterosexual men and 27"/;. had an inverted CD4/CD8 ratio but mostly without CD4 lymphopenia {CD4<04x 107/), However, some healthy uninfected people were 'physiologieally' lymphopenic without having inverted CD4/CD8 ratios. When the variations "within persons" were studied longitudinally over a 5-year period, the absolute CD4 counts tended to be fixed al different levels. As a marked contrast, over 60% of asymptomatic HIV-I ' patients exhibited low CD4 counts <04x 10"//together with inverted CD4/CD8 ratios. Such combined changes among the heterosexual and HIV-1-seronegative homosexual groups were as rare as 14% and 3%. respectively. For this reason, when the lymphoeyte tests show < 0-4 X IO**// CD4 eount and a CD4/CD8 ratio ofless than unity, the individuals need to be investigated further for ehronicity of this disorder, the signs of viral infections sueh as HIV-I and other eauses of immunodeficiency.

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Section: Discussionmentioning
confidence: 90%

“…Our analysis on 676 HIV-1 ^ individuals together with two other large-scale multi-centre studies [23,27] establish the normal values and ranges ofT lymphocyte subpopulations in blood. The groups studied above have included healthy controls, Table 1.…”

Section: Discussionmentioning
confidence: 99%

Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis
Bofill
¹
,
Jánossy
²
,
Lee
³

et al. 1992
Clinical and Experimental Immunology
196
11
87
0
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Section: Measurementsmentioning
confidence: 99%

“…The TG values were determined enzymatically using the procedure of Bucolo and David (CV 5 1.7%) [26]. CD4 T-cell counts were determined by flow cytometry in National Institute of Allergy and Infectious Disease (NIAID) Flow Cytometry Quality Assessment Program certified laboratories [27].The definition of HAART was guided by the DHHS/Kaiser Panel [28] guidelines and defined as: (a) two or more NRTIs in combination with at least one PI or one nonnucleoside reverse transcriptase inhibitor (NNRTI) (89% of observations classified as HAART); (b) one NRTI in combination with at least one PI and at least one NNRTI (6%); (c) a regimen containing ritonavir and saquinavir in combination with one NRTI and no NNRTIs (1%); and (d) an abacavir-or tenofovir-containing regimen of three or more NRTIs in the absence of both PIs and NNRTIs (4%), except for the three-NRTI regimens consisting of abacavir 1 tenofovir 1 lamivudine or didanosine 1 tenofovir 1 lamivudine. Combinations of zidovudine and stavudine with either a PI or an NNRTI were not considered HAART.…”

mentioning
confidence: 99%

Longitudinal changes in serum lipids among HIV‐infected men on highly active antiretroviral therapy
Riddler
¹
,
Li
²
,
Chu
³

et al. 2007
HIV Medicine
87
8
58
3
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ObjectiveThe aim of the study was to describe longitudinal changes in serum lipids among HIV-infected men receiving highly active antiretroviral therapy (HAART) with long-term follow-up. MethodsA total of 304 HIV-infected men who initiated HAART and who had serum lipid measurements prior to and for up to 7 years after HAART initiation were identified from the Multicenter AIDS Cohort Study (MACS). Mean levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were examined at biannual time-points. ResultsSignificant lipid changes were seen within 0.5 years of HAART initiation but increases in TC ( 1 1.09 mmol/L), LDL-C ( 1 0.57 mmol/L), HDL-C ( 1 0.16 mmol/L) and non-HDL-C ( 1 0.91 mmol/L) reached peak levels 2-3 years after HAART initiation. Declines in serum TC, LDL-C and non-HDL-C in subsequent years occurred concurrently with a substantial increase in use of lipid-lowering medications (from 1% usage pre-HAART to 43% 6-7 years after HAART initiation) but the proportion of men who either were treated with cholesterol-lowering medication or had elevated cholesterol levels (45.18 mmol/L) did not change during the 2-7-year interval after HAART. Mean HDL-C also decreased after 2-3 years and was low (o1.04 mmol/L) in 55% of HIV-infected men 6-7 years after HAART initiation. ConclusionsAtherogenic serum lipids increased early after the initiation of HAART, peaked at 2-3 years and remained high or required treatment thereafter. Low HDL-C levels persisted in the majority of men. The long-term effects of lipid abnormalities on cardiovascular risk and the effectiveness and toxicity of prolonged use of lipid-lowering medications in combination with HAART are not known.Keywords: cohort studies, dyslipidemia, HAART, HIV-1, HIV infection Introduction HIV-1 infection has been associated with reductions in serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) and with elevations in triglycerides (TG) observed later in the disease course [1][2][3]. Use of single or dual nucleoside reverse transcriptase inhibitors (NRTIs) was not associated with significant changes in serum lipid levels. However, within 2 years of the widespread availability of potent protease inhibitor (PI)-based highly active antiretroviral therapy (HAART), there were numerous reports of moderate to severe changes in serum lipids as well as other metabolic alterations [4][5][6][7][8][9][10][11][12]. These observations were initially anecdotal or based on limited case series, but in recent years large randomized clinical trials of HAART have routinely included prospective measurement of serum lipids [13,14].Several important questions regarding the impact of serum lipid abnormalities in HAART-treated individuals remain unanswered. The incidence of cardiovascular events among HAART recipients has been assessed in several large cohort and database studies [15][16][17][18][19]. In aggregate, these studies suggest a small but sig...

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“…In the United States at the end of the '80s, studies were focused on the preanalytical variables (4) and on the definition of \normal" ranges in lymphocyte immunophenotyping (2,5), also by extensively comparing sequential confidence intervals and prospective within-person deviations between patients and controls (6). This task required very intensive studies, whose need was influenced by the generalized application of the technically unsatisfactory selection of lymphocytes during data analysis using forward versus side light scatter gating at that time.…”

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confidence: 99%

Twenty years of external quality assurance in clinical cell analysis — A tribute to Jean‐Luc D'Hautcourt
Brando
¹
,
Gatti
²
,
Chianese
³

et al. 2006
Cytometry Part B Clinical
5
0
2
0
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External quality assurance (EQA) denotes the measures taken to ensure the reliability of laboratory sampling, testing, and reporting when test results are to make an impact on clinical decision making (1). EQA in its broader sense is more comprehensive than \external quality control" (EQC), since it includes the important aspects of laboratory proficiency, performance scoring, quality of advice given to clinicians, and continuous educational support.Clinical cell analysis by flow cytometry has entered the same process of development of instrumental validation, internal/external QC, and EQA as any other laboratory medicine activities during the late '80s. The outbreak of the AIDS epidemics, and the need to guide medical treatment with reliable CD4 þ T cell counts have been a stimulus to direct an esoteric, mostly experimental technology towards the same accuracy and reproducibility as has been established for routine blood testing.The progress in establishing a quality assurance process in clinical cell analysis by flow cytometry has been particularly slow, as compared to other fields of clinical pathology, for a number of reasons: the delicacy of instrumentation, the rapidly evolving hardware and software, the continuous development of new biological targets, antibody reagents and fluorochromes, and most important the lacking of any previously existing discipline to encompass all the aspects of clinical cytometry (2).During the last two decades a long and sometimes difficult process took place, complicated by multiple waves of technical development and clinical validation of many different applications such as leukemia/lymphoma immunophenotyping, CD34þ hematopoietic stem cell analysis, screening for the HLA B27 antigen, low level leucocyte counting, and many \niche" applications. The evolution of clinical cell analysis by flow cytometry is a good example of how the advent of a new technology can take advantage from the established laboratory qual-*Correspondence to: Prof. Bruno Brando,

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Quality control in the flow cytometric measurement of T-lymphocyte subsets: The Multicenter AIDS Cohort Study experience

Cited by 245 publications

References 25 publications

Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis

Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis

Longitudinal changes in serum lipids among HIV‐infected men on highly active antiretroviral therapy

Twenty years of external quality assurance in clinical cell analysis — A tribute to Jean‐Luc D'Hautcourt

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