JC virus latency in the brain and extraneural organs of patients with and without progressive multifocal leukoencephalopathy.

JC virus (JCV) is latent in the kidneys and lymphoid organs of healthy individuals, and its reactivation in the context of immunosuppression may lead to progressive multifocal leukoencephalopathy (PML). Whether JCV is present in the brains or other organs of healthy people and in immunosuppressed patients without PML has been a matter of debate. We detected JCV large T DNA by quantitative PCR of archival brain samples of 9/24 (38%) HIV-positive PML patients, 5/18 (28%) HIV-positive individuals, and 5/19 (26%) HIV-negative individuals. In the same samples, we detected JCV regulatory region DNA by nested PCR in 6/19 (32%) HIV-positive PML patients, 2/11 (18%) HIV-positive individuals, and 3/17 (18%) HIV-negative individuals. In addition, JCV DNA was detected in some spleen, lymph node, bone, and kidney samples from the same groups. In situ hybridization data confirmed the presence of JCV DNA in the brains of patients without PML. However, JCV proteins (VP1 or T antigen) were detected mainly in the brains of 23/24 HIV-positive PML patients, in only a few kidney samples of HIV-positive patients, with or without PML, and rarely in the bones of HIV-positive patients with PML. JCV proteins were not detected in the spleen or lymph nodes in any study group. Furthermore, analysis of the JCV regulatory region sequences showed both rearranged and archetype forms in brain and extraneural organs in all three study groups. Regulatory regions contained increased variations of rearrangements correlating with immunosuppression. These results provide evidence of JCV latency in the brain prior to severe immunosuppression and suggest new paradigms in JCV latency, compartmentalization, and reactivation.

Telaprevir and pegylated interferon-alpha-2a inhibit wild-type and resistant genotype 1 hepatitis C virus replication in patients.

UNLABELLED: Telaprevir (VX-950) is an orally active, specifically targeted antiviral therapy for hepatitis C virus (HCV) that has been shown to profoundly reduce plasma HCV RNA in genotype 1 patients. Using a highly sensitive sequencing assay that detects minor populations of viral variants (>or=5%), mutations were identified that conferred low-level (V36M/A, T54A, or R155K/T) or high-level (A156V/T and 36/155) resistance to telaprevir in vitro. We report a detailed kinetic analysis of these variants in 16 patients given telaprevir or telaprevir + pegylated interferon-alpha-2a (PEG-IFN-alpha-2a) for 14 days. In 4 patients who had a viral rebound on telaprevir alone, the R155K/T and A156V/T variants were detected during the initial steep decline in HCV RNA. During the rebound phase, the R155K/T and A156V/T variants were replaced by V36(M/A)/R155(K/T) double mutant variants. In the remaining 12 patients given telaprevir alone or with telaprevir/PEG-IFN-alpha-2a, the A156V/T variant was detected in some patients, but viral levels continued to decline in all patients. CONCLUSION: These studies suggest that the initial antiviral response to telaprevir is due to a sharp reduction in wild-type virus, which uncovers pre-existing telaprevir-resistant variants. In patients given telaprevir alone, viral rebound can result from the selection of variants with greater fitness. However, the combination of telaprevir and PEG-IFN-alpha-2a inhibited both wild-type and resistant variants. In the present study, every patient who began PEG-IFN-alpha-2a and ribavirin after the 14-day dosing period had undetectable HCV RNA levels at 24 weeks, indicating that telaprevir-resistant variants are sensitive to PEG-IFN-alpha-2a and ribavirin.