New optimized DNA extraction protocol for fingerprints deposited on a special self-adhesive security seal and other latent samples used for human identification.

Obtaining complete short tandem repeat (STR) profiles from fingerprints containing minimal amounts of DNA, using standard extraction techniques, can be difficult. The aim of this study was to evaluate a new kit, Fingerprint DNA Finder (FDF Kit), recently launched for the extraction of DNA and STR profiling from fingerprints placed on a special device known as Self-Adhesive Security Seal Sticker(®) and other latent fingerprints on forensic evidentiary material like metallic guns. The DNA extraction system is based on a reversal of the silica principle, and all the potential inhibiting substances are retained on the surface of a special adsorbent, while nucleic acids are not bound and remain in solution dramatically improving DNA recovery. DNA yield was quite variable among the samples tested, rendering in most of the cases (>90%) complete STR profiles, free of PCR inhibitors, and devoid of artifacts. Even samples with DNA amount below 100 pg could be successfully analyzed.

HIV-1 genetic diversity in Argentina and early diagnosis of perinatal infection.

HIV-1 diagnosis of perinatally exposed children is usually performed by molecular biology-based methods, allowing the direct detection of the virus. Thus, HIV-1 genomic variability within and across strains plays a major role in relation to the sensitivity of these tests, often leading to misdiagnosis. We describe the performance of an in-house multiplex nested PCR (nPCR) for early detection of HIV-1 infection in perinatally exposed children born in Argentina, where the percentage of diverse BF recombinants is as high as 80%. After evaluation of 1316 HIV-1 perinatally exposed children collected over a 7-year period, the specificity and sensitivity of the diagnostic nPCR was of 100% and 99.2% respectively, with only two false negative cases indicating a good performance of the diagnostic nPCR in the Argentine pediatric cohort. In search of unusual HIV-1 subtypes among 22 HIV-1 infected cases presenting partial or complete HIV-1 gene amplification failure, we performed phylogenetic and recombination analysis of a vpu-env fragment in addition to gag and env Heteroduplex Mobility Assay screening. The most unusual findings included two subtypes A and a novel BC recombinant, while the majority of the strains were a variety of different BF recombinants. These results indicate the presence of novel and heterogeneous genotypes in our country and the need of continuous viral surveillance not only for diagnostic test optimization but also for the eventual implementation of a successful vaccine.

Sequence analysis of a South American HIV type 1 BC recombinant.

We report the characterization of a near full-length sequence of a South American HIV-1 BC intersubtype recombinant, ARE195FL. This isolate contains a C(gag/pol) B(vpr/vpu/gp160(env)) C(gp41(env)/nef) mosaic structure differing from any BC full-length sequence described to date, and is the first full-length sequence obtained from a South American BC strain. Neighbor-joining analysis revealed that subtype C genomic segments of ARE195FL clustered with the South American group of subtype C strains, suggesting a local emergence of the BC recombinant. Despite having dissimilar genomic structures, ARE195FL shares a common recombination breakpoint in vif, which is a "hot spot" for recombinatory events, with the Chinese BC recombinant prototype CRF07_BC. Further full-length sequence analysis of South American HIV-1 C and BC strains is necessary to determine the relevance and spread of emerging HIV-1 BC recombinants in Latin America.

High IL-7 plasma levels may induce and predict the emergence of HIV-1 virulent strains in pediatric infection.

BACKGROUND: HIV-1 infection results in severe immunodeficiency when T-cell loss cannot be compensated. IL-7 is one of the main cytokines involved in the maintenance of T-cell homeostasis. However, IL-7 can also enhance HIV-1 replication in vivo and lead to an accelerated progression of AIDS. OBJECTIVE: The aim of our study was to evaluate if the increase of IL-7 levels in response to CD4+ T cell depletion could favor the emergence of HIV-1 strains with more aggressive phenotypes in pediatric infection. STUDY DESIGN: Plasma IL-7 levels were measured in 42 HIV-1 vertically infected infants at different times of infection, and HIV-1 isolates were obtained from primary cell cultures to determine replication rate and syncytium-inducing (SI) capability on MT-2 cell line. RESULTS: IL-7 levels were significantly higher in infants harboring HIV-1 SI strains compared to those with non-syncytium-inducing (NSI) viruses (p<0.0001). Likewise, IL-7 levels were higher in infants with rapid replicating viral strains versus those with slow replicating viruses (p=0.0006). Despite the strong negative correlation between IL-7 levels and CD4+ T lymphocyte counts (r=-0.55, p=0.0001), covariance analysis demonstrated that the high levels of IL-7 were associated with more virulent phenotype features (SI and rapid replicating strains) independently of CD4+ T cell depletion. In 19 of the 42 infants, longitudinal follow-up studies showed that SI to NSI phenotype switch can occur after HAART administration, with a reduction in IL-7 levels and an increase in CD4+ T cell counts. CONCLUSIONS: IL-7 response to T-cell depletion may enhance T-cell production, but at the same time may foster HIV-1 disease progression favoring the emergence of more virulent HIV-1 strains characterized by SI capability and rapid replication rate.

Circulation of novel HIV type 1 A, B/C, and F subtypes in Argentina.

The Argentine HIV-1 epidemic is considered to be represented mainly by subtype B and diverse B/F recombinants, with apparent absence of pure subtype F. In this study we describe three novel HIV-1 variants isolated from four infants born in different and distant provinces of Argentina. Partial analysis of different gene fragments spanning 18.5-40.8% of the HIV-1 complete genome revealed two subtype A HIV-1 strains in siblings, a B/C recombinant with a novel mosaic structure, and a putative subtype F. Characteristic patterns of genomic and amino acid sequences of the newly reported subtype F isolate suggest a closer genetic relationship to Argentine B/F recombinants than any other subtype F strain described so far, while the A and B/C subtypes found correspond to unusual genotypes in Argentina. Understanding the origin, diversity, and spread of HIV-1 strains worldwide will be necessary for the development of an effective vaccine approach.

Relevance of viral phenotype in the early AIDS outcome of pediatric HIV-1 primary infection.

In infants the clinical course of HIV-1 infection is bimodal, differing considerably from that of adults. The effect of HIV-1 phenotypic features and plasma viral load on the clinical course of infection has been well established in adults, whereas in children it remains controversial. The aim of this study was to prospectively evaluate the effect of HIV-1 replication phenotypes during the first year of primary infection in the development of premature immunosuppression and early pediatric AIDS. In 62 vertically infected children replication rates of HIV-1 isolates from primary cultures and syncytium-inducing capability in MT-2 cell line were evaluated, together with plasma viral load. It was observed that rapid replication rate and syncytium-inducing phenotype accelerate the early onset of pediatric AIDS (p = 0.02 and p = 0.04, respectively). Rapid replication kinetics was the only significantly independent variable for early clinical outcome (risk ratio, 2.48; p = 0.02). Both viral properties contributed to rapid CD4+ T-cell depletion (p = 0.05 for rapid replication rate, p = 0.01 for syncytium-inducing viral phenotype). Plasma viral burden higher than 5.5 log(10) copies/mL after 6 mo of age tended to be associated with disease progression. In conclusion, initial HIV-1 biologic features in pediatric primary infection by vertical transmission may influence the progression to early immunosuppression and development of AIDS.