A novel HIV in-vitro enhancement process aids in early detection of HIV infection.
The findings indicate that in addition to enabling early detection of infection, there is a potential for improved incidence estimations with positive public health implications, due to the low false recent rate found by the process. The World Health Organization and the U.S. Centers for Disease Control are both working toward wide acceptance of new approaches to combat the spread of HIV such as early and complete detection of HIV infections, "test and treat", and at the same time looking for better ways to determine incidence, i.e. the rate in which the epidemic is spreading.
In the reported studies, HIV tests were performed on blood samples from over 5,000 high-risk and over 3,000 low-risk subjects using the in-vitro antibody enhancement approach, called SMARTube. Based on the test results, which were obtained after the SMARTube enhancement step, using standard test kits for HIV antibodies (e.g. ELISA, rapid tests), researchers reported the following:
- Compared with the testing of regular plasma, the use of SMARTube plasma produced "no false positive results when testing a low-risk population," providing improved specificity.
- Use of the "SMARTube can identify early HIV infection, as shown by an increased detection over regular plasma from infected persons" thus improving diagnostic sensitivity.
- The SMARTube Stimulation Index (SI, the ratio of antibodies in SMARTplasma/plasma)) "indicates a low false recent rate, resulting in excellent specificity, which is essential for incidence estimations." This is key to public health efforts carrying out epidemiological studies to determine where high rates of new infections are occurring, and for monitoring the efficacy of prevention programs.
- "The Stimulation Index from two populations with the same demographics was actually different, suggesting that incidence testing using the SMARTube SI, should be done on all high-risk populations."
Research field work was carried out by independent research and public health units around the world (including the USA, Russia, Kenya, Israel, China), and was written for presentation to the 6th IAS HIV Conference in Rome by Tamar Jehuda-Cohen of the Technion Israel Institute of Technology and SMART Biotech Ltd., Israel; and by Ahmed R. Saleh and Niel T. Constantine of the Institute of Human Virology at the University of Maryland School of Medicine, Baltimore.
Stimulation Index finds marked difference in incidence'' of two similar populations
Dr. Constantine and Dr. Saleh headed the Baltimore study reported in the Rome IAS presentation involving 371 high-risk subjects from the Man Alive and the IBR clinics, both located on the same street.
When the SMARTube Stimulation Index of the two clinics was compared, there was a marked difference.
"While this is a small cross-sectional'' sample set," Dr. Constantine noted, "the SI distribution (between the two clinics) is different (and with higher SI values) in the seropositives from the population which also has higher prevalence. The results are intriguing, and we hope to do further studies that could demonstrate the ability to get confirmed incidence data."
Dr. Constantine noted: "The SMARTube technology has a high potential to be used for epidemiologic purposes where incidence estimates are needed to target the most at-risk populations for public health intervention."
The SMARTube is not a diagnostic test but a pre-test enhancement of antibody output, leading to early detection of HIV infection even prior to seroconversion
Dr. Tamar Jehuda-Cohen emphasized that the SMARTube isn''t a diagnostic test, but rather "an in-vitro pre-test method of enhancing antibody production by lymphocyte cells that were primed in-vivo by HIV in the infected person from which the blood sample was taken."
"The advantage of using SMARTube," Dr. Jehuda-Cohen added, "is that it enables very early HIV detection, giving laboratories, clinicians and researchers a tool to detect pre-seroconversion infections providing an important tool for better evaluating and understanding the early stages of the HIV infection."
She noted that the U.S. Centers for Disease Control has strongly supported the concept of "test and treat" as a major advance in helping to curb the spread of HIV infection.
"With SMARTube used in conjunction with all the readily-available diagnostic approaches, there is the opportunity to detect even the earliest stages of infection, thus capturing those infected who are at the most infectious time, and rendering prevention programs more effective." Currently, people at risk for HIV who test negative are told to come for a re-test 2-to-3 months later. "Most of them never come back," Dr. Jehuda-Cohen noted.