Abstract
Background: Demonstration and evaluation of anti
tuberculous IgA antibodies for rapid diagnosis of both
pulmonary and extra pulmonary tuberculosis.
Method: ELISA assay based on mycobacterial antigen
A60 (Anda Biologicals, France) was used on the sera
obtained from 69 cases of tuberculosis and 136 controls in
the population of Karachi, Pakistan.
Result: Of 136 controls only 7.3% were positive for IgA.
A very good serological response was observed in cases
with sputum positive active pulmonary tuberculosis,
depicting a positivity of 83.3% for IgA antibodies.
Relatively low sero positivity was seen in cases of sputum
negative active pulmonary tuberculosis compared to those
of sputum active pulmonary tuberculosis. A low positivity
of 26.3% for IgA was observed in cases of extra pulmonary
tuberculosis. In cases of healed tuberculosis 25% were
found positive for IgA. Considering all the cases of active
tuberculosis and the controls the global sensitivity of
58.4% and specificity of 92.7% were obtained when IgA
antibodies were taken into account.
Conclusion: The estimation of anti tuberculosis
antibody IgA against A60 for the rapid diagnosis is clearly
demonstrated and therefore recommended