![]() The purified protein derivative (PPD) skin test is of limited value, since it can turn positive in people who have been vaccinated with bacillus Calmette-Guerin (BCG) and in individuals who have had contact with other mycobacteria. The traditional laboratory methods used for complementation of diagnosis have their limits, such as low sensitivity of acid-fast smears in paucibacillary patients, the time needed for cultivation, with undetectable growth in only 10 to 20% of the cases, and the high costs involved in molecular detection methods, such as PCR. However, tuberculosis does not always present the classic radiological signs that allow an easy diagnosis, especially in extrapulmonary cases. The standard diagnosis is still made by clinical examination, direct sputum microscopy, and bacterial culture. Furthermore, the risk of reactivation increases as a consequence of associated conditions and pathologies, such as diabetes, cancer, chronic renal insufficiency, immune-suppressive therapy, malnutrition and, mainly, coinfection with human immunodeficiency virus (HIV). tuberculosis in its latent form, and that 5% develop active disease during the first years of infection, it is estimated that 8 million new cases of tuberculosis and 3 million deaths occur each year. Ĭonsidering that one-third of the world population carries M. tuberculosis, 40% of the individuals that become infected will develop primary active tuberculosis, and 60% remain with the latent form of the bacilli and may present extrapulmonary sites of infection, resulting from inefficient macrophage action at the beginning of exposure. Mycobacterium tuberculosis causes pulmonary tuberculosis (Tb), and the clinical manifestations of infection can be either acute, or latent and asymptomatic, depending on the intensity of the immune response mounted by the infected patient.Īfter being exposed to M. tuberculosis recombinant antigens diagnosis. The association of TbF6/DPEP antigens used in ELISA with specific patterns of reactivity determined by Western blot can help make an identification when classic methods for the diagnosis of pulmonary tuberculosis are not sufficient. Western blot specificity was 100% when antibody reactivity with different antigenic bands was analyzed and associated. ELISA sensitivity improved from 85% to 92% when the Western blot results were used. The best ELISA results were obtained with the TbF6/DPEP antigen combination, which gave 85% sensitivity and 91% specificity. Serum samples from 22 healthy individuals and from 30 patients with lung diseases other than tuberculosis were used as controls. We evaluated the sensitivity and specificity of ELISA, based on the recombinant TbF6® and TbF6/DPEP antigen and a search for reactivity patterns in the Western blot technique, using whole mycobacterium antigen. tuberculosis strain were used to detect specific IgG antibodies in sera from 52 patients with pulmonary tuberculosis, confirmed by an acid-fast smear and serum culture of these patients and that of 25 contacts. Phone: (55) 220 recombinant antigens and a crude bacterial antigen of a wild M. IVBiolab-Merieux S/A and Tropical Medicine Institute, São Paulo, SP, Brazilĭepartamento de Análises Clínicas e Toxicológicas IIClinical Hospital Faculty of Medicine of São Paulo University, São Paulo IFederal University of Santa Maria, Santa Maria, RS tuberculosis recombinant antigens diagnosisĬombined use of Western blot/ELISA to improve the serological diagnosis of human tuberculosis Two recombinant antigens and a crude bacterial antigen of a wild M. ![]()
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