In order to study the level of antibody binding to the extract antigen from Mycobacterium tuberculosis (TE antigen) in the IgG, IgA, IgM and IgE class in sera from patients with pulmonary tuberculosis, enzyme-linked immunosorbent assay was performed on 106 patients confirmed as active pulmonary tuberculosis and 30 normal healthy controls.
The results were obtained as follow:
1) The activity level (O.D. at 492nm) of IgG class to TE antigen at the serum dilution of 1：400 was 0.315±0.245 in miliary tuberculosis; minimal, 0.228±0.167; moderately advanced, 0.556±0616; far advanced, 1.116±0.651 and 0.126±0.084 in normal healths controls.
2) The activity level (O.D. at 492nm) of IgA class to TE antigen at the serum dilution of 1：12.5 was 0.320±0.231 in miliary tuberculosis; minimal, 0.606±0.557; moderately advanced, 0.727±0.589; far advanced, 1.002±0.574 and 0.183±0.123 in norma healthy controls.
3) No significant differences between tuberculous patients and normal healthy controls were observed in the activity levels of IgM and IgE classes to 73 antigen at the serum dilution of 1：25.
4) Low degree of correlation (r=0.475) between IgG class and IgA class activity was observed in tuberculous patients.
5) For the serodiagnosis of pulmonary tuberculosis, the specificity and the sensitivity in the assay of IgG class activity were 87% and 74%, respectively, whereas those in the assay of IgA class activity were 90% and 80%, respectively.
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