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PubMed1995

Evaluation of four alternative methodologies for determination of absolute CD4+ lymphocyte counts. The National Heart, Lung, and Blood Institute Retrovirus Epidemiology Donor Study.

Standard methods for determining absolute CD3+CD4+ T-lymphocyte concentrations using combined results from flow cytometry and hematology analyzers are expensive and require fresh (< 18 h old) blood. We evaluated four new "alternative" methods for determining absolute CD4+ T-lymphocyte counts; (a) the FACSCount System (Becton Dickinson Immunocytometry Systems), (b) VCS Technology/Coulter Cyto-Spheres (Coulter Corporation), (c) Zymmune CD4/CD8 Cell Monitoring Kit (Zynaxis, Inc.), and (d) TRAx CD4 Test Kit (T Cell Diagnostics). EDTA-anticoagulated whole-blood specimens from HIV-seropositive patients and anti-HIV-negative adult blood donors and staff were tested by the standard flow cytometry method on fresh blood (0-6 postphlebotomy) and by the four alternative methods at 0 to 6 h and 24 to 30 h postphlebotomy. Representative specimens (< 6 h old) were tested five times with each system to evaluate reproducibility. Correlation coefficients for absolute CD4+ counts between standard flow cytometry and the alternative methods ranged from 0.84 to 0.92 for both fresh and 24- to 30-h-old specimens. Average coefficient of variation for reproducibility ranged from 4.5 to 7.1%. The four alternative CD4+ T-lymphocyte counting methods performed well relative to standard methods. Each alternative method offers advantages over standard flow cytometry with respect to sample throughout, required technical expertise, and cost per result. These methods should facilitate wider availability of low-cost CD4 counts.

Blood Donors↗
PubMed1997

The relationship between beta-2-microglobulin, CD4 lymphocyte count, AIDS and death in HIV-positive individuals.

The relationship, in 539 individuals infected with the human immunodeficiency virus (HIV), between two prognostic markers, the CD4 count and beta-2-microglobulin (B2M), and the development of the acquired immunodeficiency syndrome (AIDS) and death was investigated. Cox proportional hazards models were used to determine the risk of AIDS or death. In a multivariate model which adjusted for demographic factors and treatment, the most recent measurements of B2M (relative hazard (RH) 1.37 per g/l higher) and CD4 count (RH 2.17 per log-unit lower) were both significantly associated with the development of AIDS. Similarly, in a multivariate model which additionally adjusted for the development of AIDS as a time dependent covariate, there was a strong relationship with risk of death for the most recent measurements of B2M (RH 1.34 per g/l higher), and CD4 lymphocyte count (RH 1.91 per log-unit lower). A difference in the level of B2M could be used among patients with similar CD4 counts as an indicator of increased risk of progression to AIDS or death. Using the most recent values of these markers provides a better estimate of the risk of AIDS or death, compared to the more common method of analysis, where baseline values of the markers are used.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Neurophysiological parameters and CD4 lymphocyte count in patients infected by human immunodeficiency virus].

INTRODUCTION AND OBJECTIVE: The human immunodeficiency virus (HIV) causes serious, irreversible, progressive deterioration of the immune and nervous systems. The main target cells are the 'helper' T lymphocytes and monocyte-macrophage cells with CD4 molecules on the surface acting as virus receptors. In this study we attempt to find whether the immune state and the nervous system are involved in parallel, or whether, on the contrary, HIV neurotropism is such that it leads to early nerve involvement, out of proportion to that of the immune system. PATIENTS AND METHODS: We studied a total of 66 persons, 30 seronegative and 36 seropositive, with different CD4 lymphocyte counts. In all cases motor and sensory conduction studies were done in the arms and legs, namely auditory, visual and somatosensory evoked potentials and also endogenous potentials (mainly P300). CONCLUSIONS: There are neurophysiological parameters which give pathological figures, even when immunity is maintained (figures of CD4 greater than 500/mm3) especially with regard to the figures for sensitivity of the legs, somatosensory evoked potentials and P300. Moreover, these are increased and others added at the same time as the CD4 count falls as the disease advances.

Adult↗
PubMed1994

OKT4 epitope deficiency in patients infected with the human immunodeficiency virus: a cause of underestimation of the CD4 lymphocyte count.

Two black patients who were infected with the human immunodeficiency virus (HIV) and who had hereditary deficiency of OKT4 epitope were investigated. The patients' lymphocytes lacked the OKT4 surface antigen but reacted with other monoclonal antibodies recognizing the CD4+ helper-inducer T lymphocytes. The CD4 lymphocyte count is a surrogate marker for clinical progression of HIV disease, but it could be unreliable in regard to patients with partial or complete OKT4 epitope deficiency.

Adult↗
PubMed1994

[The effect of the type of factor VIII concentrate on the CD4 lymphocyte count in hemophiliacs with human immunodeficiency virus infection: the results of a meta-analysis].

BACKGROUND: The administration of factor VIII concentrates of intermediate purity in HIV+ hemophiliac patients has been related with disorders of the immunologic system of these patients which may be observed in a more acute decrease in CD4 lymphocyte count in relation to that described in patients treated with products of greater purity. The present study evaluates the impact of these treatments (concentrates of intermediate or high purity) on the immune system of HIV+ hemophiliac patients by exhaustive analysis of the literature. METHODS: Meta-analysis of 8 clinical studies published between 1983 and 1993 was performed by multivariate analysis which considers the decrease in the number of CD4 lymphocytes as an indicator of the evolution of the disease. Likewise, the size of the effect and combined significance were also evaluated. RESULTS: The absolute decrease in the number of CD4 lymphocytes is significantly lower in patients treated with products of greater purity (354 +/- 52 vs 448 +/- 54 cells/microliters p = 0.037) as was the size of the effect and the different tests of combined significance. The speed of decrease was between 1.25 and 16.55 cells/microliters/year lower in the treated group than in the control (p = 0.029). CONCLUSIONS: According to meta-analysis, the factor VIII concentrates of intermediate purity influence the immune system of HIV+ hemophiliac patients to a greater extent leading to a more acute decrease in the number of CD4 lymphocytes over time. Further studies are required to confirm whether this facts leads to differences in clinical manifestations of the infection or in survival.

Adolescent↗
PubMed1998

Predictive value of quantitative plasma HIV RNA and CD4+ lymphocyte count in HIV-infected infants and children.

CONTEXT: Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic features that preclude routine extrapolation from adult studies and require specific analysis. OBJECTIVES: To evaluate the prognostic value of 2 key laboratory markers-plasma RNA and CD4+ lymphocyte count-for HIV disease progression in infants and children and to establish targeted values for optimal outcome. DESIGN: Data from a cohort of 566 infants and children who participated in a randomized, placebo-controlled trial of nucleoside reverse transcriptase inhibitors (ACTG 152) were analyzed. The trial was conducted between 1991 and 1995 and enrolled a heterogeneous cohort of antiretroviral therapy-naive children (age, 3 months to 18 years); patients had a median follow-up of 32 months. MAIN OUTCOME MEASURES: The trial clinical end points consisted of time to first HIV disease progression (growth failure, decline in neurologic or neurodevelopmental function, opportunistic infections) or death. RESULTS: Baseline plasma RNA levels were high (age group medians, 5 x 10(4) to >10(6) copies/mL), and both baseline RNA and CD4+ lymphocyte count were independently predictive of subsequent clinical course. Risk reduction for disease progression between 49% and 64% was observed for each log10 reduction in baseline RNA and was linear without suggestion of a threshold or age effect. Disease progression predictive power was enhanced by the combined use of plasma RNA and CD4+ cell count. Marker values of less than 10000 copies/mL for plasma RNA and greater than 500 x 10(6)/L (<6.5 years of age) or greater than 200 x 10(6)/L (>6.5 years) for CD4+ cell count were associated with a 2-year disease progression rate of less than 5%. CONCLUSIONS: Two key laboratory markers--plasma RNA and CD4+ lymphocyte count-are independent predictors of clinical course among HIV-infected infants and children. The linear, age-independent relationship between log10 plasma RNA and relative risk of disease progression strongly supports therapeutic efforts to achieve plasma virus levels as low as possible.

Adolescent↗
PubMed1998

Serum malondialdehyde in HIV-seropositive children negatively correlates with CD4+ lymphocytes count.

Human immunodeficiency virus (HIV) infection is associated with oxidative stress as it has been demonstrated in adult-seropositive individuals. We show in this study that serum malondialdehyde (MDA) concentration of HIV-infected children was significantly higher than in control children. A negative correlation (r = -0.515) was found in HIV-infected children between their CD4+ lymphocyte count, and MDA concentration but not with serum antioxidant status. The increase of MDA concentration in HIV-seropositive children confirms the involvement of oxidative stress in the pathophysiology of this infection also in childhood. Because of the importance of oxidative stress and antioxidants for HIV viral replication, the adequacy of an adjuvant therapy with antioxidants should be considered; an adequate candidate for it could be N-acetylcysteine.

Biomarkers↗
PubMed2003

When to begin highly active antiretroviral therapy? Evidence supporting initiation of therapy at CD4+ lymphocyte counts <350 cells/microL.

We assessed the risk of acquired immunodeficiency syndrome (AIDS)-related opportunistic illness or death among persons first prescribed highly active antiretroviral therapy (HAART) in January 1996 or later in the Centers for Disease Control and Prevention's Adult and Adolescent HIV Spectrum of Disease Project. Patients were included if they were naive to antiretroviral drugs and had no history of AIDS-related opportunistic illness. Risk was assessed as a function of CD4+ lymphocyte count and human immunodeficiency virus load at the time of initiation of HAART in a Cox proportional hazards model. Hazard ratios for AIDS or death were 6.3, 3.5, and 1.7 for persons with baseline CD4+ cell counts of 0-49, 50-199, and 200-349 cells/microL, respectively, compared with the referent (CD4+ cell count > or =500 cells/microL). HAART should not be deferred until the CD4+ cell count reaches <200 cells/microL. The increased hazard associated with CD4+ cell counts of 200-349 cells/microL was modest but supports initiation of HAART at CD4+ cell counts <350 cells/microL, particularly in patients with high virus loads.

Adolescent↗
PubMed1991

Long-term human immunodeficiency virus infection in asymptomatic homosexual and bisexual men with normal CD4+ lymphocyte counts: immunologic and virologic characteristics.

From a prospective cohort study, 24 asymptomatic men were identified who had been antibody positive for human immunodeficiency virus (HIV) for at least 5 years (median = 9.1) with CD4+ lymphocyte counts greater than or equal to 400 cells/mm3. Of these "nonprogressors", 23 (96%) had evidence of HIV infection by either HIV culture or the polymerase chain reaction (PCR) for HIV DNA, although only 1 (4%) had a positive assay for HIV RNA (by PCR) and no one was positive for p24 antigen. Compared with 24 antibody-negative men and 14 men with AIDS, nonprogressors had higher CD8+ counts and lower natural killer cell activity. Nonprogressors had higher beta 2-microglobulin levels than did seronegative controls, suggesting some degree of immune system activation. Compared with men with AIDS, nonprogressors seemed to have a stronger antibody response to six different HIV-related proteins but did not differ significantly in neutralizing antibody or antibody-dependent cellular cytotoxic activity.

Adult↗
PubMed1994

Use of CD4 lymphocyte count to predict long-term survival free of AIDS after HIV infection.

OBJECTIVE: To estimate the probability of remaining free of AIDS for up to 25 years after infection with HIV by extrapolation of changes in CD4 lymphocyte count. DESIGN: Cohort study of subjects followed from time of HIV seroconversion until 1 January 1993. Creation of model by using extrapolated linear regression slopes of CD4 count to predict development of AIDS after 1993. SETTING: Regional haemophilia centre in teaching hospital. SUBJECTS: 111 men with haemophilia infected with HIV during 1979-85. Median length of follow up 10.1 years, median number of CD4 counts 17. The model was not fitted for three men because only one CD4 measurement was available. MAIN OUTCOME MEASURES: Development of AIDS. INTERVENTIONS: From 1989 prophylaxis against candida and Pneumocystis carinii pneumonia and antiretroviral drugs when CD4 count fell below 200 x 10(6)/l. RESULTS: 44 men developed AIDS up to 1 January 1993. When AIDS was defined as a CD4 count of 50 x 10(6)/l the model predicted that 25% (95% confidence interval 16% to 34%) would survive for 20 years after seroconversion and 18% (11% to 25%) for 25 years. Changing the CD4 count at which AIDS was assumed to occur did not alter the results. Younger patients had a higher chance of 20 year survival than older patients (32% (12% to 52%) for those aged < 15, 26% (14% to 38%) for those aged 15-29, and 15% (0% to 31%) for those aged > or = 30). CONCLUSIONS: These results suggest that even with currently available treatment up to a quarter of patients with HIV infection will survive for 20 years after seroconversion without developing AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Relationship of CD4 lymphocyte counts to survival in a cohort of hemophiliacs infected with HIV. Multicenter Hemophilia Cohort Study.

Although CD4 positive lymphocyte counts are important predictors of clinical events in persons infected with human immunodeficiency virus (HIV), little is known about their predictive value for survival. We analyzed CD4 counts obtained regularly since 1983 with regard to survival in a multicenter cohort study of 921 HIV-infected hemophiliacs of whom 177 have died. Dates of seroconversion were determined from stored serum samples. Cumulative mortality and actuarial survival rates were calculated from the first time the mean of two consecutive CD4 counts decreased from levels of > 500 to 200-499, 100-199, 50-99, and < 50 cells/microliter. The death rate per 100 patient years of observation was 0.87 (95% CI 0.27, 1.47) for those with CD4 counts of > 500 cells/microliter and increased progressively to 26.23 (95% CI 21.29, 31.17) for those with CD4 counts of < 50/microliter. HIV-related deaths occurred in 50 of 58 who died with CD4 counts of < 300/microliter compared to 0 of 6 who died with CD4 counts of > 500/microliter. The median CD4 count most proximal to death was 39.5 (range, 1-945). The 10-year actuarial estimate of survival from seroconversion was 77.3 +/- 2% for 546 persons who seroconverted at age > or = 18 years compared to 90.5 +/- 2% for 375 persons who seroconverted at age < 18. Survival decreased at each CD4 level to a median of 27 months at CD4 counts of < 50/microliter. At each CD4 level, younger patients survived longer than older patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

HIV-1 and HIV-2 dual infection: lack of HIV-2 provirus correlates with low CD4+ lymphocyte counts.

OBJECTIVE: We conducted this study to genetically characterize dual infection in individuals demonstrating a dual serological profile. METHODS: All subjects were first evaluated by immunoblot for antibody reactivity to the major viral antigens for HIV-1 and HIV-2. Sera were judged to be dual-seropositive if they reacted with strong and equal intensity with the envelope antigens of both HIV-1 and HIV-2 and were confirmed with type-specific recombinant env peptides. We used nested polymerase chain reaction (PCR) to amplify proviral gag and env sequence from peripheral blood mononuclear cell (PBMC) DNA from HIV-1- and HIV-2-infected individuals. Positive amplification was detected after Southern blot hybridization. RESULTS: Plasmid dilution and mixing showed equivalent sensitivity of HIV-1 and HIV-2 primers that was not altered by heterologous target sequences. The DNA PCR showed 100% sensitivity and specificity for detection of monotypic HIV infection. Serologically defined HIV-dual reactives were evaluated by this assay, with 100% detection in female sex workers (21 out of 21), but only 38.5% detection (five out of 13) in hospitalized patients; all being HIV-1 positive only. The lack of HIV-2 proviral signal was significantly correlated with low CD4+ lymphocyte counts (Pvalue = 0.04). CONCLUSION: The results suggest that HIV dual infection may not be a static condition. Levels of HIV-2 may decrease with disease progression or sequester in tissue reservoirs; our results may also suggest that HIV-1 effectively overgrows HIV-2 in the dually exposed host individual.

Blotting, Southern↗
PubMed2000

Both serum HIV type 1 RNA levels and CD4+ lymphocyte counts predict clinical outcome in HIV type 1-infected subjects with 200 to 500 CD4+ cells per cubic millimeter. AIDS Clinical Trials Group Study 175 Virology Study Team.

To evaluate HIV-1 RNA and CD4+ cell responses to therapy as predictors of clinical progression and to evaluate levels and trends of these markers prior to clinical failure, HIV-1 RNA measurements were retrospectively obtained on subjects who progressed to AIDS or death and a random sample of subjects who did not. Samples were taken from AIDS Clinical Trials Group Study 175, a randomized trial comparing nucleoside analog therapies in subjects with CD4+ cell counts of between 200 and 500 cells/mm3. HIV-1 RNA and CD4+ cell count independently predicted clinical progression. Risk of subsequent progression is best captured by the change to the last measured value for CD4+ cell count and the area under the curve minus baseline, a measure of viral replication over time, for HIV-1 RNA. Subjects who failed had lower CD4+ cell counts, greater rates of CD4+ cell decline, and higher HIV-1 RNA levels, but not greater rates of HIV-1 RNA increase than subjects who did not. Subjects who maintained more than 200 CD4+ cells/mm3 and fewer than 10,000 copies of HIV-1 RNA per milliliter had low risk of progression. During the first few months of therapy, treatments are best monitored by regular HIV-1 RNA and less frequent CD4+ cell measurements. Thereafter, both markers should be monitored on a similar schedule to identify rapidly declining CD4+ cell counts, or adverse levels of either. These results further delineate the prognostic significance of HIV-1 RNA and CD4+ cell count and should help to better define their utility in the practice setting.

Adult↗
PubMed2001

Relationship between antibody-dependent cellular cytotoxicity, plasma HIV type 1 RNA, and CD4+ lymphocyte count.

To explore the role of antibody-dependent cellular cytotoxicity (ADCC) in controlling HIV-1 infection, ADCC was compared with plasma RNA and CD4+ cell count in 40 patients not receiving antiretroviral therapy and in seven patients after the initiation of treatment. Among untreated patients, ADCC effector cell function of peripheral blood mononuclear cells, measured by (51)Cr release assay, correlated inversely with viral load (R = -0.42, p = 0.007) and directly with CD4+ cell count (R = 0.52, p = 0.001). On the other hand, HIV-1-specific ADCC antibody level correlated directly with viral load, but only among patients with high CD4+ cell counts. Therapy-induced changes in ADCC effector cell function correlated strongly with changes in CD4+ cell count (R = 0.86, p = 0.014), whereas there was no consistent pattern of change in ADCC antibody with therapy. In a novel assay, ADCC reduced virus yield from CD4+ lymphocytes infected with a primary HIV isolate. ADCC may contribute to control of viremia, and CD4+ lymphocytes likely play a role in ADCC effector and antibody functions.

Anti-HIV Agents↗