Study of the antibody response against Mycobacterium tuberculosis antigens in Warao Amerindian children in Venezuela

Memórias do Instituto Oswaldo Cruz

Z Araujo²  Jh De Waard¹  C Fernández De Larrea²  D López²  C Fandiño²  A Maldonado²  E Hernández²  Y Ocaña²  R Ortega²  M Singh¹  Tom Hm Ottenhoff¹  Sm Arend¹  J Convit¹ 

[1],Facultad de Medicina Escuela de Medicina

关键词: tuberculosis (TB);    Warao Amerindians;    tuberculin skin test (TST);    IgA;    IgG;    IgE;    secretory IgA (sIgA);   

DOI  :  10.1590/S0074-02762004000500011

来源: SciELO

【 摘 要 】

This study was aimed at investigating alternate methods for serodiagnosis of tuberculosis (TB), which are needed because bacteriologic diagnosis of childhood TB is difficult. A selection of 80 serum and saliva samples were tested from Warao indigenous children under 15 years of age; 34 high TB suspects (28 positive and 6 negative for the tuberculin skin test, TST) and 46 healthy contact children (32 positive and 14 negative for the TST). Several enzyme-linked immunosorbent assay (ELISA) serological tests were developed to test for Mycobacterium tuberculosis-specific antibodies, including serum IgA, IgG, IgE, and secretory IgA (sIgA) in saliva against 3 specific antigens (PPD, HSP60, 38 kDa). Of these, 2 antigens, PPD and 38 kDa, showed significantly higher reactivity. The sensitivity and specificity of these tests for diagnosis remained limited, between 26.5% and 38.2%, and 77.4% and 97%, respectively. Of all the samples studied and combinations realized between all isotypes and antigens combined with 3 isotypes (anti-PPD IgG, IgE, and anti-38kDa sIgA) managed to detect the largest number of patients, showing an improved sensitivity level of 64.7%, although specificity levels dropped to 81.8%. These results were compared with the Omega diagnostics commercial kit results. The commercial kits showed significantly lower reactivity (sensitivity of 20% and 13.33% to Myco G and Complex Plus, respectively) and a specificity of 100%. This study shows that in indigenous populations of Venezuela, where invasive procedures cannot be used to select samples but evaluation with a chest X-ray for radiological studies is available, the combination of 3 specific isotypes may be a useful tool to increase diagnostic accuracy with pulmonary TB in this population, when used together with clinical and epidemiological criteria.

【 授权许可】

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