Viral Load and Neuropsychological Functioning in HIV Seropositive Individuals:A Preliminary Descriptive Study

We have theorized a direct relationship between viral burden and deleterious effects on the central nervous systems. It was hypothesized that HIV+ individuals would manifest poorer neuropsychological functioning after increased viral load. To address this, we compared viral burden to neuropsychological performance in subjects who participated in ACTG 116-118. Plasma samples and neuropsychological assessments completed at the same time were available for 64 observations on 21 subjects. Subjects who had a viral peak of over 1000 TCID per ml were classified as high viral load, those who did not as low viral load. Mean performances of the high viral load subjects were poorer, even though baseline performances were slightly poorer in the low viral load group. Mean post-viral peak performances were poorer than pre-viral peak performances. Declines in neuropsychological performance were found significantly more often in the high viral load group. These findings support the viral load hypothesis.

The Safety of Discontinuation of Maintenance Therapy for Cytomegalovirus (CMV) Retinitis and Incidence of Immune Recovery Uveitis Following Potent Antiretroviral Therapy

BACKGROUND

Reconstitution of immune function during potent antiretroviral therapy can prompt discontinuation of maintenance cytomegalovirus (CMV) therapy but has also been associated with sight-threatening inflammatory conditions including immune recovery uveitis (IRU).

METHOD

Patients with inactive CMV retinitis and a CD4+ cell count above 100/mm3, receiving CMV therapy and stable combination antiretroviral therapy, were assigned to one of two groups based on willingness to discontinue CMV therapy.

RESULTS

Thirty-eight participants were enrolled: 28 discontinued anti-CMV therapy (Group 1) and 10 continued CMV treatment (Group 2). Median on-study follow-up was 16 months. One Group 1 participant who experienced an increase in plasma HIV viral load and a decline in CD4+ cell count developed confirmed progression of CMV retinitis. Progression or reactivation CMV retinitis was not observed among Group 2. IRU was present at study entry in 3 participants. Six participants in Group 1 and 3 participants in Group 2 developed IRU on-study. CMV viremia was not detected in any participants, and urinary shedding of CMV was intermittent.

CONCLUSION

Recurrence of CMV retinitis following discontinuation of anti-CMV therapy among patients with antiretroviral-induced increases in CD4+ cell count was rare. However, IRU was common in both those who maintained and discontinued anti-CMV therapy.

Residual human immunodeficiency virus (HIV) Type 1 RNA and DNA in lymph nodes and HIV RNA in genital secretions and in cerebrospinal fluid after suppression of viremia for 2 years

Residual viral replication persists in a significant proportion of human immunodeficiency virus (HIV)-infected patients receiving potent antiretroviral therapy. To determine the source of this virus, levels of HIV RNA and DNA from lymphoid tissues and levels of viral RNA in serum, cerebrospinal fluid (CSF), and genital secretions in 28 patients treated for < or =2.5 years with indinavir, zidovudine, and lamivudine were examined. Both HIV RNA and DNA remained detectable in all lymph nodes. In contrast, HIV RNA was not detected in 20 of 23 genital secretions or in any of 13 CSF samples after 2 years of treatment. HIV envelope sequence data from plasma and lymph nodes from 4 patients demonstrated sequence divergence, which suggests varying degrees of residual viral replication in 3 and absence in 1 patient. In patients receiving potent antiretroviral therapy, the greatest virus burden may continue to be in lymphoid tissues rather than in central nervous system or genitourinary compartments.

Evidence of a source of HIV type 1 within the central nervous system by ultraintensive sampling of cerebrospinal fluid and plasma

Defining the source of HIV-1 RNA in cerebrospinal fluid (CSF) will facilitate studies of treatment efficacy in the brain. Four antiretroviral drug-naive adults underwent two 48-hr ultraintensive CSF sampling procedures, once at baseline and again beginning on day 4 after initiating three-drug therapy with stavudine, lamivudine, and nelfinavir. At baseline, constant CSF HIV-1 RNA concentrations were maintained by daily entry of at least 10(4) to 10(6) HIV-1 RNA copies into CSF. Change from baseline to day 5 ranged from -0.38 to -1.18 log(10) HIV-1 RNA copies/ml in CSF, and from -0.80 to -1.33 log(10) HIV-1 RNA copies/ml in plasma, with no correlation between CSF and plasma changes. There was no evidence of genotypic or phenotypic viral resistance in either CSF or plasma. With regard to pharmacokinetics, mean CSF-to-plasma area-under-the-curve (AUC) ratios were 38.9% for stavudine and 15.3% for lamivudine. Nelfinavir and its active M8 metabolite could not be accurately quantified in CSF, although plasma M8 peak level and AUC(0-8hr) correlated with CSF HIV-1 RNA decline. This study supports the utility of ultraintensive CSF sampling for studying HIV-1 pathogenesis and therapy in the CNS, and provides strong evidence that HIV-1 RNA in CSF arises, at least in part, from a source other than plasma.

Nucleoside analogs plus ritonavir in stable antiretroviral therapy-experienced HIV-infected children: a randomized controlled trial. Pediatric AIDS Clinical Trials Group 338 Study Team

CONTEXT

Although protease inhibitors are used routinely in adults with human immunodeficiency virus (HIV) infection, the role of these drugs in the treatment of clinically stable HIV-infected children is not clear.

OBJECTIVE

To evaluate the safety, tolerance, and virologic response produced by a change in antiretroviral therapy in HIV-infected children who were clinically and immunologically stable while receiving previous therapy.

DESIGN

The Pediatric AIDS Clinical Trials Group 338, a multicenter, phase 2, randomized, open-label controlled trial conducted from February 6 to April 30, 1997 (patient entry period); patients were followed up for 48 weeks.

SETTING

Pediatric HIV research clinics in the United States and Puerto Rico.

PATIENTS

Two hundred ninety-seven antiretroviral-experienced, protease inhibitor-naive, clinically stable HIV-infected children aged 2 to 17 years.

INTERVENTIONS

Children were randomized to receive zidovudine, 160 mg/m2 3 times per day, plus lamivudine, 4 mg/kg 2 times per day (n = 100); the same regimen plus ritonavir, 350 mg/m2 2 times per day (n = 100); or ritonavir, 350 mg/m2 2 times per day, and stavudine, 4 mg/kg 2 times per day (n = 97).

MAIN OUTCOME MEASURE

Plasma HIV-1 RNA levels at study weeks 12 and 48, compared among the 3 treatment groups.

RESULTS

At study week 12, 12% of patients in the zidovudine-lamivudine group had undetectable plasma HIV RNA levels (<400 copies/mL) compared with 52% and 54% of patients in the 2- and 3-drug ritonavir-containing groups, respectively (P<.001). Through study week 48, 70% of children continued receiving their ritonavir-containing regimen. At study week 48, 42% of children receiving ritonavir plus 2 nucleosides compared with 27% of those receiving ritonavir and a single nucleoside had undetectable HIV RNA levels (P = .04); however, similar proportions in each group continuing initial therapy had HIV RNA levels of less than 10000 copies/mL (58% vs 48%, respectively; P = .19).

CONCLUSIONS

In our study, change in antiretroviral therapy to a ritonavir-containing regimen was associated with superior virologic response at study week 12 compared with change to a dual nucleoside analog regimen. More children receiving ritonavir in combination with 2 compared with 1 nucleoside analog had undetectable HIV RNA levels at study week 48.

Virologic and immunologic response to nucleoside reverse-transcriptase inhibitor therapy among human immunodeficiency virus-infected infants and children

Plasma human immunodeficiency virus RNA and CD4 lymphocyte response to nucleoside reverse-transcriptase therapy were evaluated in a large, comparative pediatric trial. Both baseline values and changes in the two laboratory markers over time correlated well with clinical outcome and possessed independent predictive value. In comparison of RNA reduction from baseline between the dideoxyinosine (ddI) and zidovudine+ddI therapeutic arms, marginal superiority of the combination arm was not correlated with an observed clinical benefit. Despite the size of this trial and the significantly higher rate of clinical end points in the zidovudine monotherapy group, attempts to establish surrogacy for plasma RNA were difficult. Nevertheless, plasma RNA and CD4 lymphocyte count together possess strong clinical predictive power and are valuable tools for both the clinician and the evaluation of new therapies.

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.

CSF, plasma viral load and HIV associated dementia

Plasma viral burden has proven valuable in predicting the future course of systemic HIV related disease and the response to treatment. It is not known whether plasma or cerebrospinal fluid (CSF) viral burden can be used to predict onset of or response to treatment of nervous system disease. We propose a model of viral load mediated neurotoxicity underlying peripheral and central HIV associated neurological disease. The objective of this preliminary study was to assess the relationship of HIV associated neurological disease to quantitative viral load in plasma and CSF. 47 subjects (HIV- = 10, HIV+ = 37) participated in the study. Plasma and CSF samples were collected within a 3 h window. RT-PCR (Roche Amplicor Monitor) was utilized to assess HIV-1 RNA viral load in both plasma and cell free (centrifuged) CSF. Subjects underwent concurrent comprehensive neurological and neuropsychological evaluations. In general, systemic viral load, as measured in plasma, was greater than that found in cell free CSF. Cell free CSF HIV RNA viral load was significantly correlated with neurological dysfunction, whereas plasma viral load was not. The sole subject with an elevated CSF viral load (> 5 Log 10), had HIV associated dementia (HAD) on clinical examination.

Stabilities of free and complexed human immunodeficiency virus p24 antigens during short- and long-term storage

By the standard p24 assay there was a 25 to 27% decrease in free p24 antigen in serum after storage at 4 degrees C over 14 days but no loss at -70 degrees C. There was no loss at either temperature by the immune complex dissociation (ICD) procedure. Furthermore, there was no significant loss of detectable p24 in serum by either the ICD or the standard p24 assay after 700 days of storage at -70 degrees C.

The relation of virologic and immunologic markers to clinical outcomes after nucleoside therapy in HIV-infected adults with 200 to 500 CD4 cells per cubic millimeter. AIDS Clinical Trials Group Study 175 Virology Study Team

BACKGROUND

We studied measures of human immunodeficiency virus (HIV) replication, the viral phenotype, and immune function (CD4 cell counts) and the relation of changes in these indicators to clinical outcomes in a subgroup of patients in a controlled trial of early antiretroviral treatment for HIV, the AIDS Clinical Trials Group Study 175.

METHODS

The 391 subjects, each of whom entered the study with a single screening CD4 cell count of 200 to 500 per cubic millimeter, were randomly assigned to receive zidovudine alone, didanosine alone, zidovudine plus didanosine, or zidovudine plus zalcitabine. Plasma concentrations of HIV RNA were assessed in 366 subjects, and viral isolates from 332 subjects were assayed for the presence of the syncytium-inducing phenotype.

RESULTS

After eight weeks, the mean (+/-SE) decrease from base line in the concentration of HIV RNA, expressed as the change in the base 10 log of the number of copies per milliliter, was 0.26+/-0.06 for patients treated with zidovudine alone, 0.65+/-0.07 for didanosine alone, 0.93+/-0.10 for zidovudine plus didanosine, and 0.89+/-0.06 for zidovudine plus zalcitabine (P<0.001 for each of the pairwise comparisons with zidovudine alone). Multivariate proportional-hazards models showed that higher base-line concentrations of plasma HIV RNA, less suppression of plasma HIV RNA by treatment, and the presence of the syncytium-inducing phenotype were significantly associated with an increased risk of progression to the acquired immunodeficiency syndrome and death. After adjustment for these measures of viral replication and for the viral phenotype, CD4 cell counts were not significant predictors of clinical outcome.

CONCLUSIONS

Both the risk of the progression of HIV disease and the efficacy of antiretroviral therapy are strongly associated with the plasma level of HIV RNA and with the viral phenotype. The changes in the plasma concentration of HIV RNA predict the changes in CD4 cell counts and survival after treatment with reverse-transcriptase inhibitors.

Rapid detection of viral-specific antibodies by enzyme-linked immunosorbent assay (ELISA)

The development of three separate rapid ELISAs for detecting antibodies in host serum to three different viruses is described. These include: 1. A direct antigen assay using enzyme labelled anti-canine Ig for detecting antibodies to canine parvovirus, 2. A competitive ELISA using a feline infectious peritonitis virus-specific monoclonal antibody labelled with enzyme, and 3. A competitive ELISA using an equine infectious anemia virus-specific monoclonal antibody and enzyme labelled antigen, p. 26. The utility and benefits of each of the three approaches is emphasized.