Japanese investigators develop new tuberculosis test
The researchers said that the current tuberculin skin test used to indicate Mycobacterium tuberculosis infection has many limitations, including being confounded by BCG vaccination and by the presence of nontuberculosis mycobacteria.
After identifying several antigens that are absent from BCG vaccine as well as from most nontuberculosis mycobacteria, the investigators used them in a whole blood interferon-gamma assay as a diagnostic test in BCG-vaccinated persons.
Utilizing a group of 216 BCG-vaccinated Japanese adult student nurses who had no identifiable risk of tuberculosis exposure, they found that the specificity of their new test was 98.1 percent. (The specificity of a test is the percentage of people reliably classified as not having the disease.) Employing the same test on a group of 118 patients with diagnostic culture-confirmed M. tuberculosis infection who had received no therapy, they found a sensitivity of 89 percent. (Sensitivity to a test is the percentage of people reliably classified as having the disease.)
The specificity of the tuberculin skin test in the study was 35.4 percent, but was only 10 percent in public reports in Japan.
The investigators attributed the poor skin test specificity to a widespread use of the BCG vaccine in that country. Commenting in a editorial on the study in the same issue of the journal, Peter F. Barnes, M.D., of the Center for Pulmonary and Infectious Disease Control, University of Texas Health Center, Tyler, Texas, wrote that the research offered the most convincing evidence to date that the interferon-gamma-based tests are substantially more specific in BCG-vaccinated persons. He points out that the most critical issue for further evaluation of the interferon-gamma-based test is to determine its sensitivity for detection of latent tuberculosis infection.
The study appears in the first issue for July 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
For the complete text of these articles, please see the American Thoracic Society Online Web Site at http://www.atsjournals.org. For either contact information or to request a complimentary journalist subscription to ATS journals online, or if you would like to add your name to the Society's twice monthly journal news e-mail list, contact Cathy Carlomagno at 212-315-6442, or by e-mail at ccarlomagno@thoracic.org
Contact: Cathy Carlomagno
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212-315-6442
American Thoracic Society
Japonezã anchetatorii dezvolta noi de tuberculozã de test - Japanese investigators develop new tuberculosis test - articole medicale engleza - startsanatate