Naturally occurring mutations to HCV protease inhibitors in treatment-naïve patients.

Background: Protease inhibitors (PIs) to treat hepatitis C (HCV) virus infection have been approved and others are under development.

Results: The aims of this study were to illustrate natural polymorphisms in the HCV protease and measure the frequency of PI resistance mutations in different HCV genotypes from PI-naïve patients.Direct sequencing of HCV NS3/4A protease was performed in 156 HCV patients naïve to PIs who were infected with genotype 1a (n = 31), 1b (n = 39), 2 (n = 30), 3 (n = 33) and 4 (n = 23).

Accumulation of defective HIV-1 variants in a patient with slow disease progression.

Viral population in a long term non progressor carrying CRF02-AG HIV-1 virus variants with a truncated RT gene and attenuated virus replication was analyzed. The proportion of mutant and wild-type RT sequences was determined by clonal analysis of HIV-1 DNA and RNA from blood samples and peripheral blood mononuclear cell (PBMC) culture supernatants. Recombinant HIV-1 strains were generated by reverse genetics to evaluate the replicative capacity of RT variants in PBMC cultures.

Amino acid insertions at position 35 of HIV-1 protease interfere with virus replication without modifying antiviral drug susceptibility.

Among 1330 patients undergoing highly active antiretroviral therapy (HAART), 3 showed 1 or 2 amino acid (aa) insertions at position 35 of the HIV-1 protease gene. Protease genes containing aa insertions, either in the presence (ins35G+res.muts, ins35TN+res.

Assays for determination of HIV resistance to antiviral drugs.

Resistance to antiretroviral drugs is one of the major pitfalls of combined treatment of HIV infection. Thus, timely identification of drug resistant HIV strains and precise evaluation of the level of resistance to the different antiretroviral drugs are crucial in the management of treated patients. Phenotypic determination of antiretroviral drug resistance evaluates the ability of an HIV strain to replicate in the presence of drug(s).

Clinically-based determination of safe DNAemia cutoff levels for preemptive therapy or human cytomegalovirus infections in solid organ and hematopoietic stem cell transplant recipients.

Transplantation Centers using human cytomegalovirus (HCMV) antigenemia-based preemptive therapy will need to replace in the near future the antigenemia assay with a more standardized and automatable assay, such as a molecular assay quantifying HCMV DNA in blood (DNAemia). Thus, in view of replacing antigenemia with clinically safe cutoff values, DNAemia levels corresponding to antigenemia cutoffs guiding HCMV preemptive therapy were determined retrospectively in solid organ and hematopoietic stem cell transplant recipients (HSCTR) using an "in-house" quantitative PCR (QPCR) method. Since preemptive therapy had prevented appearance of HCMV disease in all patients tested, DNA cutoffs determined retrospectively had to be considered as safe clinically as antigenemia cutoffs used prospectively.