It is important to discriminate between tuberculosis and tuberculosis-like disease by Mycobacteria other than tuberculosis in the serodiagnosis of tuberculosis. But because common antigens share among Mycobacteria, their antigenicities to hum-,,.n are similar. Therefore degree of cross-reactivity of antibody in the sera of patients with tuberculosis between M. tuberculosis and Mycobacteria other than tuberculosis should be checked to increase the specificity in the serodiagnosis of tuberculosis.
The activity levels of IgG antibody in the sera of 106 patients confirmed as active pulmonary tuberculosis and 30 normal healthy control person to the pressate extract antigen (TE, BE, AE, and FE antigen) from M. tuberculosis, M. bovis, M. avium, and M. fortuitum were measured by enzyme-linked immunosorbent assay and the cross reactivity of IgG antibody with mycobacterial species was analyzed.
The results were as follows;
1. The activity level (O.D: at 492nm) of IgG to TE antigen in sera of patients with pulmonary tuberculosis was 0.228±0.167 in minimal tuberculosis; moderately advanced, 0.556±0.616; far advanced, 1.116±0.651 and 0.315±0.245 in miliary tuberculosis.
2. The activity level (O.D. at 492nm) of IgG to BE antigen in sera of patients with pulmonary tuberculosis was 0.190±0.162 in minimal tuberculosis; moderately advanced, 0.337±0.361; far advanced, 0.713±0.460 and 0.204±0.162 in miliary tuberculosis.
3. The activity level (O. D. at 492nm) of IgG to AE antigen in sera of patients with pulmonary tuberculosis was 0.165±0.114 in minimal tuberculosis; moderately advanced, 0_392±0.494; far advanced, 0.751±0.512 and 0.233±0.191 in miliary tuberculosis.
4. The activity level (O.D. at 492nm) of IgG to FE antigen in sera of patients with pulmonary tuberculosis was 0.280±0.227 in minimal tuberculosis; moderately advanced, 0.460±0.564; far advanced, 0.845±0.573 and 0.257±0.103 in miliary tuberculosis.
5. The activity level (O.D. at 492nm) of IgG in sera of healthy control person was 0.126±0.084 to TE antigen, 0.105±0.041to BE antigen, 0.103±0.052 to AE antigen, and 0.095±0.061 to FE antigen.
6. Degree of correlation(r) in activity level of IgG between TE antigen and BE antigen was 0.905 ; between TE antigen and AE antigen, 0.760; between TE antigen and FE antigen, 0.790, and between AE antigen and FE antigen, 0:945.
7. As O.D. above 0.200 was determined positive for the serodiagnosis of pulmonary tuberculosis, the sensitivity and specificity in ELISA using TE antigen were 80% and 87% respectively, whereas, in the case of using BE antigen, 66% and 100%; in the case of using AE antigen, 62% and 100 %, and in the case of using FE antigen, 72% and 93%, respectively.
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