IgA immune response against the mycobacterial antigen A60 in patients with active pulmonary tuberculosis

Respiration. 1996;63(5):292-7. doi: 10.1159/000196563.


Searching for IgG and IgM against the mycobacterial antigen A60 has been recognized as a potential diagnostic tool for pulmonary tuberculosis. The role of detection of anti-A60 IgA in improving diagnostic accuracy of serology is not well known. In this study we measured with ELISA serum levels of both anti-A60 IgG and IgA in 216 subjects. 88 healthy volunteers (44 PPD- and 44 PPD+), 44 patients suffering from nontuberculous lung disease and 15 subjects with healed pulmonary tuberculosis constituted the control population; 69 patients with active pulmonary tuberculosis (35 cavitary forms, 26 productive forms and 8 miliary forms) were examined. The sensitivity of IgG test was 73.9% in pulmonary tuberculosis (77.1% in cavitary forms, 65.4% in productive forms, 87.5% in miliary forms); the specificity of the test was 95.9%. For the IgA test we observed a sensitivity of 72.5% (74.3 in cavitary forms, 69.2% in productive forms, 75.0 in miliary forms) and a specificity of 93.9%. Combination of the two tests increased the sensitivity to 84.0% (+10.1% compared to IgG test, +11.5% compared to IgA test); the specificity decreased to 92.5% (-3.4% vs. IgG test; -1.4 vs. IgA test). In conclusion, the combined use of evaluation of anti-A60 IgG and IgA increases the accuracy of serological diagnosis of pulmonary tuberculosis.

MeSH terms

  • Adult
  • Antigens, Bacterial / immunology*
  • Female
  • Humans
  • Immunoglobulin A / analysis
  • Immunoglobulin A / immunology*
  • Immunoglobulin G / analysis
  • Male
  • Middle Aged
  • Sensitivity and Specificity
  • Serologic Tests
  • Tuberculin / immunology*
  • Tuberculosis, Pulmonary / immunology*


  • Antigens, Bacterial
  • Immunoglobulin A
  • Immunoglobulin G
  • Tuberculin
  • mycobacterial A60 antigen