title: Study of the antibody response against Mycobacterium tuberculosis antigens in Warao Amerindian children in Venezuela.
abstract: 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.
authors.affiliation: Cátedra de Immunología, Escuela de Medicina José María Vargas, Facultad de Medicina, Universidad Central de Venezuela, Apartado 4043, Caracas 1010A, Venezuela. zaraujo@telcel.net.ve
authors.forename: Z
authors.initials: Z
authors.lastname: Araujo
authors.forename: J H de
authors.initials: JH
authors.lastname: Waard
authors.forename: C
authors.initials: C
authors.lastname: Fernández de Larrea
authors.forename: D
authors.initials: D
authors.lastname: López
authors.forename: C
authors.initials: C
authors.lastname: Fandiño
authors.forename: A
authors.initials: A
authors.lastname: Maldonado
authors.forename: E
authors.initials: E
authors.lastname: Hernández
authors.forename: Y
authors.initials: Y
authors.lastname: Ocaña
authors.forename: R
authors.initials: R
authors.lastname: Ortega
authors.forename: M
authors.initials: M
authors.lastname: Singh
authors.forename: Tom H M
authors.initials: TH
authors.lastname: Ottenhoff
authors.forename: S M
authors.initials: SM
authors.lastname: Arend
authors.forename: J
authors.initials: J
authors.lastname: Convit
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis* / Q000276:immunology; D007199:Indians, South American; D007223:Infant; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D014687:Venezuela / Q000453:epidemiology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007136:Immunoglobulins; C072681:Mycobacterium tuberculosis antigens