[The usefulness of in vitro interferon-gamma assay for differential diagnosis between intestinal tuberculosis and Crohns disease].
It is difficult to clinically and endoscopically differentiate intestinal tuberculosis (ITB) and Crohns 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.



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.



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 Behcets enterocolitis. Of the 40 patients with negative results, 38 patients (95%) were diagnosed as CD; one as Behcets 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.



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.
Lee
Jung Nam
JN
Department of Internal Medicine, Pusan National University College of Medicine, Busan, Korea.
Ryu
Dong Yup
DY
Park
Sung Han
SH
You
Hyun Seok
HS
Lee
Bong Eun
BE
Kim
Dong Uk
DU
Kim
Tae Oh
TO
Heo
Jeong
J
Kim
Gwang Ha
GH
Song
Geun Am
GA
Kim
Suk
S
Park
Do Youn
DY
D000293:Adolescent; D000328:Adult; D000368:Aged; D003424:Crohn Disease / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011933:Reagent Kits, Diagnostic; D012189:Retrospective Studies; D014385:Tuberculosis, Gastrointestinal / Q000175:diagnosis*
D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma