New Evidence Helpful In Distinguishing,Crohn's Disease?CD? From Intestinal Tuberculosis ?ITB? By The Methodswidely Used Clinically

Aims:(1) Search for new evidence helpful in distinguishing,Crohn's disease(CD) from intestinal tuberculosis (ITB) by the methodswidely used clinically; (2) Use FQ-PCR for the detection ofMycobacterium tuberculosis (MTB) DNA to set up a real-timequantitative assay method, and identify its value for diagnosing ITB;(3) Explore the association between Mycobacterium paratuberculosis(MP) and CD with the hope that FQ-PCR might help the diagnosis ofCD.Methods: (1) A retrospective study involving 33 patientsdiagnosed with Crohn's disease and 34 patients diagnosed withintestinal tuberculosis was analysed. Comparison of CD with ITB onconventional clinical manifestation, radiological and histopathologicalfindings, et al.(2) FQ-PCR was performed on 36 endoscopic biopsyspecimens from patients with ITB (30 paraffin blocks, 6 fresh frozenblocks) and 36 specimens (including surgically resected specimensand endoscopic biopsy specimens, 31 paraffin blocks, 5 flesh frozenblocks) from these patients. We also chose 34 controlled specimens,including UC and normal tissues. DNA was amplified by FQ-PCRwith the IS6110 primers. In an analysis of 36 specimens from patientswith ITB, results of FQ-PCR were compared with Ziehl-Neelsen (ZN)staining for acid-fast bacilli (AFB). The sensitivity and specificity ofFQ-PCR were analyzed: (3) Primers were designed to detect a smallfragment (129bp) of the MP specific IS900 gene in CD, ITB, UC andcontrols without inflammatory bowel disease. Results: (1) CD and ITB were lack of specific characteristics.Endoscopy and histological examination could help identify thediagnosis. (2) Of the 36 patients diagnosed with ITB, MTB IS6110DNA was positive in 23 and was negative in 13. The sensitivity ofFQ-PCR was 63.89%, significantly higher than ZN staining (36.11%),and the specificity was 83.33%. The positive predictive value was79.31%, and the negative predictive value was 69.77%. The positivespecimens comprised MTB with the range from 2.44×10^-4/cell to 2.26×10¹/cell. (3) Amplification of the 129bp fragment of the IS900 genewas not detected MP DNA in CD and ITB, however a new sequenceexisting in 8 specimens of CD and 5 specimens of ITB was found inour study.Conclusions: (1)It is vexing to diagnose CD or ITB; (2) FQ-PCRis a rapid and reliable assay in the diagnosis of ITB, especially whenthe ZN staining is negative.(3) By performing FQ-PCR with specimensfrom patients with CD and controls, no association between CD andinfection with MP could be found. Maybe there exists some othercommon germ in both CD and ITB.