The Usefulness of In Vitro Interferon-gamma Assay for Differential Diagnosis between Intestinal Tuberculosis and Crohn's Disease / 대한소화기학회지

ABSTRACT

BACKGROUND/AIMS: It is difficult to clinically and endoscopically differentiate intestinal tuberculosis (ITB) and Crohn's disease (CD). The aim of this study was to evaluate the usefulness of in vitro interferon-gamma (INF-gamma) assay for differential diagnosis between ITB and CD. METHODS: Sixty patients for whom differential diagnosis between ITB and CD was difficult were enrolled between January 2007 and January 2009. The INF-gamma-producing T-cell response to early secreted antigenic target 6 and culture filtrate protein 10 were measured by T-SPOT.TB blood test in vitro. We evaluated the usefulness of T-SPOT.TB blood test by comparing its results with the final diagnosis. RESULTS: Twenty and forty patients were revealed to be positive and negative in T-SPOT.TB blood test, respectively. Of the 20 patients found to be positive, 12 patients (60%) were finally diagnosed as ITB, 6 patients as CD, and 2 patients as Behcet's enterocolitis. Of the 40 patients with negative results, 38 patients (95%) were diagnosed as CD; one as Behcet's enterocolitis; one as nonspecific colitis; none as ITB. The sensitivity and specificity of T-SPOT.TB blood test for ITB were 100% and 83.3%, respectively. Positive and negative predictive values of T-SPOT.TB blood test for ITB were 60.0% and 100%, respectively. CONCLUSIONS: When differential diagnosis between ITB and CD is difficult, T-SPOT.TB blood test may be a helpful and rapid diagnostic tool to exclude ITB. Prospective large-scaled studies are required for further evaluation of the usefulness of T-SPOT.TB blood test for differential diagnosis between ITB and CD.