title: Determination of levels of specific IgA to the HspX recombinant antigen of Mycobacterium tuberculosis for the diagnosis of pleural tuberculosis.
abstract: OBJECTIVE
  To evaluate the accuracy of determining specific IgA to HspX recombinant antigen in pleural fluid and serum samples for the diagnosis of pleural tuberculosis in patients with pleural effusion.
  
  
  METHODS
  This was a cross-sectional study. Serum and pleural fluid samples of patients with pleural effusion and suspected of having pleural tuberculosis were tested with indirect ELISA in order to determine the optical density of specific IgA to HspX.
  
  
  RESULTS
  We evaluated serum and pleural fluid samples from 132 patients: 97 diagnosed with pleural tuberculosis (study group) and 35 diagnosed with pleural effusion due to other causes (control group). The determination of IgA in pleural fluid satisfactorily discriminated between pleural tuberculosis patients and control patients. The sensitivity of the test in pleural fluid and in serum was 69% and 30%, respectively, whereas the specificity was 83% and 84%, respectively.
  
  
  CONCLUSIONS
  Our data suggest that this test can be used in the diagnosis of pleural tuberculosis. Further studies, involving larger patient samples and different epidemiological scenarios, are warranted.
authors.affiliation: Laboratory of Immunopathology of Infectious Diseases, Federal University of Goiás Institute of Tropical Pathology and Public Health, Goiânia, Brazil.
authors.forename: Loanda Carvalho Sant' Ana
authors.initials: LC
authors.lastname: Limongi
authors.forename: Liliane
authors.initials: L
authors.lastname: Olival
authors.forename: Marcus Barreto
authors.initials: MB
authors.lastname: Conde
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Junqueira-Kipnis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000276:immunology*; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis* / Q000276:immunology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; C118127:HspX protein, Mycobacterium tuberculosis; D007070:Immunoglobulin A