IgA immune response against the mycobacterial antigen A60 in patients with active pulmonary tuberculosis.
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.
Alifano
M
M
Institute of Respiratory Disease, University of Naples Federico II, Italy.
Sofia
M
M
Mormile
M
M
Micco
A
A
Mormile
A F
AF
Del Pezzo
M
M
Carratù
L
L
D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology*; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014373:Tuberculin / Q000276:immunology*; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
D000942:Antigens, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014373:Tuberculin; C055539:mycobacterial A60 antigen