New tools in HCV diagnosis, in light of the enhanced awareness and the new drugs for treatment: SMARTube and stimmunology.

With improved HCV therapy, challenges regarding HCV diagnosis, such as seronegative window period, false positive readings, and differentiation between recent, chronic, and resolved infections, are of increasing importance. To address these challenges an innovative device--SMARTube HIV & HCV--was used. Blood samples were tested for anti-HCV antibodies before and after incubation in the SMARTube, which promotes the in vitro stimulation of in vivo HCV primed lymphocytes, thus enhancing levels of anti-HCV antibodies. Comparing antibody levels, in concordant samples before and after SMARTube, yielded the Stimulation Index (SI). Among 5888 fresh blood samples, from various populations and regions worldwide, 641 were seropositive using plasma, while SMARTube processing (yielding enriched plasma, termed SMARTplasma) enabled diagnosis of 10 additional carriers in high-risk cohorts, that is, earlier detection. Using SMARTplasma eliminated all false positive results, using the current assays. In addition we show that SI calculation may serve as an important tool for differentiating between those who recently seroconverted, carriers of long-term infection, and those who have cleared the virus. SMARTube and the SI could lead to better, more informative diagnosis of HCV infections and play an important role in changing the way we treat both the infected individuals and the epidemic as a whole.

The challenges of hepatitis C diagnosis and the potential role of Stimmunology™ to address them.

The diagnosis of HCV infection is hindered by the long seronegative window period, the high rate of false-positives and the need to differentiate between current and cleared infection. Stimmunology™ is a technology by which antibody production can be stimulated, even in a whole blood sample, in vitro. Such stimulation leads to an increase in HCV antibody levels in the blood sample, enabling the detection of HCV infection prior to seroconversion. This increase in the levels of the HCV antibodies, which can be achieved within days of infection, practically resolves the window period problem. The detection of the infection, even at its seronegative stage, translates to increased diagnostic sensitivity and the concomitant dilution of 'noise' in the sample leads to a >96% reduction in the false-positive rate. The stimulation step acts upon HCV-primed lymphocytes in the blood sample; therefore, only in the presence of infection would the increased antibody levels be detected, thus differentiating between current and cleared infection. Clinical diagnostic data have been collected to provide insight as to how the diagnosis of HCV infection may be improved using this technology.

Detecting seronegative-early HIV infections among adult versus student Kenyan blood donors, by using Stimmunology.

BACKGROUND: Undetectable HIV infection in blood banks poses a serious threat to public health. Thus, donations from high school students are preferred over adult samples in Kenyan blood banks, due to lower HIV infection prevalence within this population, as detected by conventional serology testing. However, the number of recently infected individuals remains difficult to identify, as HIV-induced immunological window periods can span months. This study focuses on the potential contribution of a novel mode of diagnostic testing in revealing early, seronegative HIV carriers. METHODS AND FINDINGS: Stimmunology, an in vitro lymphocyte stimulation technique, was used to detect early HIV infection among random samples of adult and adolescent blood donors. The Stimmunology protocol unveiled a significant number of early, pre-seroconversion HIV carriers both among adult and teenage Kenyan populations, undetected by typical serological diagnostic kits. Both populations demonstrated a significant increase in HIV-specific antibody formation following activation using the Stimmunology assay. The younger population exhibited a higher proportion of early HIV infection (0.45) than the adult (0.27) population. CONCLUSIONS: While blood samples of young donors are preferred over adult donations, these data demonstrate a worrisome ratio of early, seronegative HIV carriers within this population. This simple, cost-effective, and reliable HIV-boosting antibody assay can be used in a resource-poor setting to increase blood supply safety and quality. Incorporation of Stimmunology into basic blood bank testing and into diagnostic protocols can also decrease undesirable disease transmission.

HIV type 1 infection among Ethiopian immigrants to Israel: enhanced in vitro antibody stimulation for estimating the length of the window period.

The window period between infection and seroconversion varies based on viral genetics, dose and route of transmission, host genetics, and environmental factors. The in vitro Stimmunology blood pretreatment assay was utilized to promote the synthesis of HIV-specific antibodies in efforts to define the window period between infection and seroconversion. Ethiopians seeking immigration to Israel while in refugee camps provided a unique cohort to perform a comparative analysis of the window period between HIV-1 infection and diagnosis utilizing conventional Ab-ELISA and our laboratory established an in vitro Stimmunolog assay. This population was considered unique due to its exposure to an environment with a high seroprevalence rate for a defined period of time. Unlinked blood samples were tested and validated before and after Stimmunology. Diagnostic screening was conducted in Israel. A total of 285 and 537 random samples were tested from the 1992 and 1998 immigrant population, respectively. Analysis of HIV prevalence, incidence, and window period length among the immigrants was measured by comparing results obtained on samples prior to and following analysis by Stimmunology as compared with standard ELISA-based assay. This novel assay that promotes the in vitro stimulation of antibody synthesis led to the diagnosis of 2.7% and 0.36% of the 1992 and 1998 immigrant groups, respectively, as HIV infected individuals during the window period. Using mathematical modeling, the length of the window period in the surveyed population was estimated to range from 2 to 5 months. Stimmunology-aided detection of early seronegative HIV-infected individuals provided a reliable and consistent mode of identifying infection in seronegative HIV-1-infected individuals. Applying mathematical modeling to the data obtained enabled us to define the window period length, which was found to extend beyond previous estimates. These results suggest a need for the reevaluation of the techniques that are employed to assess the true incidence and prevalence of HIV-1 infection, especially in populations within sub-Saharan Africa.