Enzyme-linked immunospot assay for the diagnosis of latent tuberculosis infection in rheumatic diseases / 中华风湿病学杂志

ABSTRACT

Objective To evaluate a new enzyme-linked immunospot assay (TSPOT-TB) for the diagnosis of latent tuberculosis infection in patients with rheumatic diseases.Methods The rapid TSPOT-TB assay was applied to detect ESAT-6 and CFP-10 specific T cells in blood samples from 126 rheumatic disease patients.A PPD skin test was performed on all patients simultaneously.Results The positive rate of TSPOT assay was 23.8% and that of PPD skin test was 34.9%.The overall agreement between the 2 tests was 71.4%.Among PPD (-) patients (n=82),11 were TSPOT (+) ( 13.4% ).Among PPD (+) patients (n=44),25 were TSPOT(-) ( 56.8% ).The patients who got BCG vaccination showed a significantly higher rate of positive results of PPD skin test than those who did not(41% vs 19%,P＜0.05).While in TSPOT assay,the BCG vaccination did not show any influence on TSPOT results (22% vs 27%,P＞0.05).Conclusion BCG vaccina-tion affects the results of PPD test in patients with rheumatic diseases,but has no influence on TSPOT results.The infection rate of latent tuberculosis in patients with rheumatic diseases in our study is 23.8% detected by TSPOT.