Evaluation of the potential diagnostic value of cytotoxic T lymphocyte-associated antigen-4 in differentiation of active and latent tuberculosis infection / 中华传染病杂志

ABSTRACT

Objective To analyze the expressions of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) in the peripheral blood of patients with active tuberculosis (ATB ) or latent tuberculosis infection (LTBI) ,and to evaluate its diagnostic value in differentiation of ATB and LTBI .Methods Forty-eight patients including 18 ATB cases and 30 LTBI cases were continuously enrolled from Wuxi No . 5 People′s Hospital and Huashan Hospital affiliated to Fudan University from January 2011 to March 2013 .Flow cytometry was applied to detect the CTLA-4 expression in CD4+CD25+ FoxP3+ T cells in the peripheral blood of the 48 subjects .CTLA-4 levels were compared using non-parametric Mann-Whitney U test .Results The median percentage of CTLA-4+ Treg in CD4+ CD25+ Foxp3+ Treg cells of ATB patients was 18 .95％ (quantile range13 .86％ ,27 .73％ ) ,and that in LTBI patients was 6 .67％(quantile range5 .74％ ,9 .59％ ) ,which was statistically significant (U=18 .0 , P< 0 .01) .Receiver operating curve (ROC) based on the CTLA-4 expression indicated that the area under the curve was 0 .96 , with the optimum cut-off value of 13 .25％ .Thus ,the sensitivity and specificity for the diagnosis of ATB were 86 .7％ and 94 .4％ ,respectively .Conclusion CTLA-4 has highly sensitivity and specificity for the differential diagnosis of ATB and LTBI whose interferon-gamma releasing assays are all positive ,which may also provide meaningful clue for the study of pathogenesis of ATB .