Study of the antibody response against Mycobacterium tuberculosis antigens in Warao Amerindian children in Venezuela
Mem. Inst. Oswaldo Cruz
;
99(5): 517-524, Aug. 2004. ilus
Article
in English
| LILACS
| ID: lil-386685
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 percent and 38.2 percent, and 77.4 percent and 97 percent, 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 percent, although specificity levels dropped to 81.8 percent. These results were compared with the Omega diagnostics commercial kit results. The commercial kits showed significantly lower reactivity (sensitivity of 20 percent and 13.33 percent to Myco G and Complex Plus, respectively) and a specificity of 100 percent. 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.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Tuberculosis
/
Immunoglobulins
/
Antibodies, Bacterial
Type of study:
Diagnostic study
/
Observational study
/
Prevalence study
/
Risk factors
Limits:
Adolescent
/
Child
/
Child, preschool
/
Female
/
Humans
/
Infant
/
Male
Country/Region as subject:
South America
/
Venezuela
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
2004
Type:
Article
/
Project document
Affiliation country:
Germany
/
Netherlands
/
Venezuela
Institution/Affiliation country:
GBF and Lionex GmbH/DE
/
Leiden University Medical Center/NL
/
Universidad Central de Venezuela/VE
/
Universidade Central de Venezuela/VE
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