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RESEARCH BRIEFSResearchers Report Quick, Inexpensive HIV TestResearchers in the HMS Division of AIDS, working with scientists at the University of Texas, Austin, have invented a device that could revolutionize the way HIV-infected people are monitored and treated in the world's poorest and most vulnerable populations. The tool--which works by capturing immune cells on a microchip and then analyzing them--is fast, inexpensive, and ultimately expected to fit in the palm of the hand. And it requires no more than a drop or two of blood from a simple finger stick. Bill Rodriguez, John McDevitt, and their colleagues have used a laboratory version of the device on the blood from 10 HIV-infected patients and 10 healthy volunteers and found that it produced accurate CD4 counts. It also did so quickly, in less than 10 minutes. Their findings were presented on Feb. 13 at the 10th Congress on Retroviruses and Opportunistic Infections in Boston. Future versions of the device with the capacity to monitor viral load as well as CD4 counts are currently being developed. "The ultimate goal and the thing that excites all of us here is that in principle and in the not-too-distant future, we could have a hand-held device that a relatively untrained person could use in the field, in a rural or resource-poor area of Africa or southeast Asia or Haiti, or anywhere, and be able to get the critical tests that are needed to monitor HIV in minutes," said Rodriguez, HMS instructor in medicine at Massachusetts General Hospital. "Right now it is just impossible." Finding an inexpensive and practical way to diagnose and monitor HIV infection in remote settings has been one of the biggest scientific challenges to emerge from the global AIDS crisis. Current methods rely on bulky and expensive machines like a flow cytometer, which uses optical techniques to measure molecules. The idea for a cheaper, more portable device came when Bruce Walker, HMS professor of medicine at MGH and director of the School's Division of AIDS, heard about a platform for microdiagnostics developed by McDevitt and his colleagues at the University of Texas, Austin. The Texas researchers had been using the device to measure proteins and electrolytes. Working with Rodriguez and Walker, they redesigned the device into a miniaturized flow cytometer to capture and measure CD4 cells. In the new system, CD4 cells are caught and stabilized on a microchip and then inserted into the mini-flow cytometer to be imaged and analyzed for vital information. "We are taking HIV testing from something the size of a refrigerator to something the size of a small hand-held camera," Rodriguez said. He estimates that the new device will cost between $600 and $800, a fraction of the $70,000 to $100,000 price tag on current HIV-testing equipment. The cost of a single test to monitor an individual patient's CD4 count will be about a dollar and a half, compared to $25 for existing methods. "In parallel with making the drugs cheaper, we are making the tests cheaper," said Rodriguez. "The combination is necessary to really treat people with HIV around the world." --Misia Landau
Lawsuits for Medical Monitoring May Aid Public HealthResearchers at HSPH and HMS have brought to light what they see as a "striking development in the law" and one that they say may improve public health if used selectively. Lawyers representing people who have no current injury but have been exposed to an allegedly harmful pharmaceutical product are increasingly suing drug manufacturers to pay for medical monitoring, ensuring early detection if adverse effects do arise. A leading example of the trend is the lawsuits that mounted after the termination of the Women's Health Initiative study of hormone replacement therapy. That trial was halted last July after findings showed a link between the therapy and an increased risk of breast cancer. Based on their investigation of court decisions in the recent cases of the diet drugs fenfluramine and phentermine ("fen-phen") and the hypoglycemic drug troglitazone (Rezulin), the researchers conclude that this expansion in tort law may benefit the public's health if applied in the right situations. Authored by David Studdert and Michelle Mello, both HSPH assistant professors of health policy and law, and Troyen Brennan, HSPH professor of health policy and management and HMS professor of medicine at Brigham and Women's Hospital, the study appears in the Feb. 19 Journal of the American Medical Association. In the fen-phen litigation, a nationwide class action suit led to a settlement in which patients who had contracted valvular heart disease were compensated and those who had taken the drugs but remained healthy were given free access to ongoing diagnostic testing. Before the monitoring program could become law, Judge Louis Bechtle evaluated it against eight criteria for fairness, which included the latency of disease progression, existence of a sensitive and low-cost diagnostic test, prevalence of disease among those exposed, and effectiveness of disease monitoring. The program met the criteria and was approved. The litigation over Rezulin, however, in which plaintiffs claimed liver dysfunction from the drug, had a different outcome. In a class action suit that went to trial in West Virginia, the judge used the same eight criteria for the medical monitoring component of the case and found that it would be inappropriate on virtually every count. The nature of the damage caused by the drug and the limited options for its detection and treatment did not warrant monitoring. The authors praise these considered rulings and the Bechtle criteria, in particular. They say the criteria give a useful framework for the legal and public health systems to work collaboratively in this emerging area of tort law. --Robert Neal
Pilot HIV Screening Finds Infection 43 Percent Higher than for Self-referralsA program in Massachusetts shows that routine testing for HIV in hospitals with a high prevalence of HIV could significantly increase the identification of new infections. It is estimated that one third of the 900,000 HIV-infected people in the U.S. are unaware of their status. In 2001, the Centers for Disease Control and Prevention (CDC) set out guidelines for routine HIV counseling, testing, and referral (HIV CTR) that recommend offering HIV CTR to all patients in hospitals with HIV prevalence rates of one percent or more. But in practice, routine testing is rarely done. The program, called Think HIV, is a collaboration among researchers from the HMS Division of AIDS, Boston University School of Public Health, and the Massachusetts Department of Public Health. It set out to implement the CDC guidelines in the urgent care centers of four Massachusetts hospitals that had the highest rates of HIV reporting. The results were presented by Rochelle Walensky, HMS instructor in medicine at Massachusetts General Hospital, on Feb 11 at the 10th Conference on Retroviruses and Opportunistic Infections in Boston. All people who entered the urgent care centers were given the opportunity to speak in a private room with a multilingual health counselor, where they were offered an HIV test with an oral swab. The program emphasized patient follow-up to make sure they returned for results. If a patient was found to be HIV-positive, a clinic intake nurse took responsibility for ensuring that the patient received follow-up care. Of the 2,444 people who accepted testing--about 37 percent of those who were offered it--the program uncovered 48 new HIV cases in the first nine months, a prevalence rate of 2.0 percent. Walensky said that this rate is 43 percent higher than that of current self-referral efforts. The Think HIV program tested a much greater proportion of people who considered themselves at low risk. The researchers also found a greater incidence of HIV among people who reported having a negative HIV test in the previous year (2.20 per 100 person years vs. 1.0 per 100 person years statewide), suggesting that this population could also benefit from routine screening. Walensky pointed out that the program not only identifies new cases but ensures that HIV-infected patients receive follow-up care, which has not always happened in other HIV screening programs. The team is currently looking at the cost-effectiveness of this type of screening using a computer simulation model that weighs the added expense of HIV CTR for implementation on a larger scale. "Now we would like this to be a paradigm for a national expansion," Walensky said. --Courtney Humphries |
