Evaluation of an automated extraction system in combination with Affigene CMV Trender for CMV DNA quantitative determination: comparison with nested PCR and pp65 antigen test.

CMV viral load quantitation is a powerful tool to assist clinicians in making accurate diagnoses, managing post-transplant CMV disease and monitoring antiviral therapy. The aim of this study was to evaluate the performance of Affigene CMV Trender for CMV viral load determination used in combination with a non-dedicated nucleic acid extraction system (BioRobot MDx) for high-throughput routine. Linearity, reproducibility and sensitivity were examined. Clinical samples were used to compare results obtained with the Affigene CMV Trender, with an "in house" nested PCR used for routine diagnosis and with pp65 antigenemia. The results indicated that the test is linear in the range of 1.81-5.18 Logcopies/ml and that sensitivity is 77 copies/ml. The concordance of the Affigene CMV Trender with nested PCR was high, (k=0.91, IC 95%=0.82-1.00), whereas a substantial concordance with pp65 antigenemia was observed (k=0.64, IC 95%=0.54-0.73). In conclusion, combined use of a non-dedicated automated nucleic acid extraction method with the Affigene CMV Trender results in an accurate high throughput system, suitable for routine laboratory monitoring of CMV infection.

Heterogeneity of HVR-1 quasispecies is predictive of early but not sustained virological response in genotype 1b-infected patients undergoing combined treatment with PEG- or STD-IFN plus RBV.

ISDR mutation pattern and HVR-1 quasispecies were analyzed in HCV genotype 1b-infected patients treated with either PEG- or STD-IFN plus ribavirin, in order to find virological correlates of therapy outcome. ISDR region analysis, performed at baseline (T0) and at 4 weeks of therapy (T1), indicated that ISDR mutation pattern was not predictive of response to treatment. Moreover, no selection of putative resistant strains in the first month of therapy was observed. Viral load was not correlated with any parameter of HVR-1 heterogeneity. Among the HVR-1 heterogeneity parameters considered, complexity was inversely correlated to viral load decline at T1. In univariate analysis, complexity, proportion of non synonymous substitutions (NS) and NS/S ratio were lower in patients showing virological response at 6 months of treatment. Complexity was the only parameter independently associated with both decline of viral load at T1 and virological response after 6 months, even after adjustment for confounding variables. At the end of treatment or later, these correlations were lost. Evolution pattern of the HVR-1 quasispecies indicated a strong selective pressure in sustained responders, with complete substitution of pre-existing quasispecies, while minor changes occured in non responders. In relapsers both patterns were present at a similar rate. In conclusion, this study shows that HVR-1 heterogeneity may be involved in the early response to combined IFN-RBV therapy. The loss of correlation between viral heterogeneity and therapy outcome at 6 months of therapy, or later, suggests that other factors may play a role in maintaining sustained response to treatment.

Significant reduction in HIV-1 plasma viral load but not in proviral infected cells during sub-optimal antiretroviral therapy.

Attempts to eradicate HIV infection through highly active antiretroviral therapy (HAART) in the very early stages of the infection have failed due to the resumption of viral replication from unknown reservoirs. It has been postulated that antiretroviral therapy capable of suppressing viral replication, as shown by reduction of HIV-RNA copies in plasma and lymph nodes, should have less effect on the number of HIV-DNA carrying cells in the same districts. To test this hypothesis, plasma viremia and the proportion of provirally infected cells in peripheral blood and in lymph nodes were measured in patients at 3 and 6 months of treatment with zidovudine plus lamivudine. All patients showed a significant decrease in plasma viremia at 3 months that was maintained at 6 months (mean values of 1.6 +/- 0.6 log10 from baseline). Conversely the proportion of HIV-DNA carrying cells slightly declined at 3 months but remained substantially stable thereafter both in peripheral blood and in lymph nodes. Taken together these data suggest that this therapeutic regimen, although sub-optimal, is effective in significantly reducing the virus production by productively infected cells but does not seem to substantially affect the load of provirally infected cells.