Comparison of Roche MONITOR and Organon Teknika NucliSens assays to quantify human immunodeficiency virus type 1 RNA in cerebrospinal fluid

Factors influencing cerebrospinal fluid and plasma HIV-1 RNA detection rate in patients with and without opportunistic neurological disease during the HAART era

Background

In the central nervous system, HIV replication can occur relatively independent of systemic infection, and intrathecal replication of HIV-1 has been observed in patients with HIV-related and opportunistic neurological diseases. The clinical usefulness of HIV-1 RNA detection in the cerebrospinal fluid (CSF) of patients with opportunistic neurological diseases, or the effect of opportunistic diseases on CSF HIV levels in patients under HAART has not been well defined. We quantified CSF and plasma viral load in HIV-infected patients with and without different active opportunistic neurological diseases, determined the characteristics that led to a higher detection rate of HIV RNA in CSF, and compared these two compartments.

Methods

A prospective study was conducted on 90 HIV-infected patients submitted to lumbar puncture as part of a work-up for suspected neurological disease. Seventy-one patients had active neurological diseases while the remaining 19 did not.

Results

HIV-1 RNA was quantified in 90 CSF and 70 plasma samples. The HIV-1 RNA detection rate in CSF was higher in patients with neurological diseases, in those with a CD4 count lower than 200 cells/mm³, and in those not receiving antiretroviral therapy, as well as in patients with detectable plasma HIV-1 RNA. Median viral load was lower in CSF than in plasma in the total population, in patients without neurological diseases, and in patients with toxoplasmic encephalitis, while no significant difference between the two compartments was observed for patients with cryptococcal meningitis and HIV-associated dementia. CSF viral load was lower in patients with cryptococcal meningitis and neurotoxoplasmosis under HAART than in those not receiving HAART.

Conclusion

Detection of HIV-1 RNA in CSF was more frequent in patients with neurological disease, a CD4 count lower than 200 cells/mm³ and detectable plasma HIV-1. Median HIV-1 RNA levels were generally lower in CSF than in plasma but some patients showed higher CSF levels, and no difference between these two compartments was observed in patients with cryptococcal meningitis and HIV-associated dementia, suggesting the presence of intrathecal viral replication in these patients. HAART played a role in the control of CSF HIV levels even in patients with cryptococcal meningitis and neurotoxoplasmosis in whom viral replication is potentially higher.

Two phases of HIV RNA decay in CSF during initial days of multidrug therapy

BACKGROUND

Defining cellular and tissue sources of HIV-1 in CSF is important for understanding disease pathogenesis and optimal therapies for HIV infection in the brain.

OBJECTIVE

To identify the time of maximal viral decay in CSF during the initial days of antiretroviral therapy.

METHODS

Serial CSF and plasma data were available from four adults who underwent ultraintensive CSF sampling for 48 hours at baseline and again beginning 72 hours after starting antiretroviral therapy. Regression lines were generated using HIV-1 RNA data from 17 on-treatment serial CSF samples obtained at 3-hour intervals. Viral RNA was quantified by Nuclisens and Amplicor HIV-1 Monitor assays.

RESULTS

Extrapolation of regression lines intersected baseline below actual baseline CSF HIV-1 RNA concentrations, indicating that virus decayed most rapidly on days 1 through 3 with half-lives of no more than 0.9 to 2.8 days. Half-lives on days 4 and 5 ranged from 1.3 to 4.9 days. Plasma data also showed early rapid decay.

CONCLUSIONS

Multiple phases of viral decay suggest that virus in CSF originates from at least two sources during untreated, asymptomatic HIV-1 infection. The short half-life indicates that the primary source is CD4+ T cells. Sampling during days 1 through 3 and different stages of disease will better define sources of virus.