[Detection of specific IgG and its specific circular immune complex in the diagnosis of tuberculosis].

In order to search for the immunological diagnostic methods of pulmonary tuberculosis, extrapulmonary tuberculosis and its autoimmunopathy, we determined the PPD-C IgG and PPD-C IgG present in CIC by means of PPD-C-based ELISA in 50 tuberculosis patients, 20 patients with lung cancer and 30 normal subjects. The positive rates of serum PPD-C IgG in tuberculosis, lung cancer and normal subjects were 62%, 5% and 6.7% respectively. The positive rates of PPD-C IgG present in CIC were 86%, 10% and 6.7% respectively. The sensitivity of PPD-C IgG present in CIC was 86% and the specificity was 92%. It was suggested that CIC surface PPD-C IgG was more valuable in the diagnosis of tuberculosis.