PCR法检测结核分枝杆菌DNA在鉴别克罗恩病与肠结核中的价值

摘要

AIM: To identify the feasibility of using polymerase chain reaction (PCR) for detection of Myco-bacterium tuberculosis ( MTB) DNA in biopsy tissues and surgical specimens in the form of paraffin blocks from the patients with Crohn disease (CD) or intestinal tuberculosis (ITB). METHODS: DNA was amplified by PCR using the primers selected from IS6110 in MTB chromosome in ITB and CD specimens. The PCR products were confirmed by polyacrylamide gel electrophoresis and PCR-direct sequencing. The relationship between PCR results and pathological features was also analyzed. RESULTS: MTB DNA was positive in 32% and 0% cases of the pathologically or clinically confirmed 25 ITB and 25 CD patients, respectively. The sensitivity of MTB DNA PCR for differential diagnosis of ITB and CD was 32% , significantly higher than that of acid fast staining (8% ) and caseation necrosis (12% ). Specificity, positive and negative predictive values were 100% , 100% and 59.5% , respectively. The positive rate of MTB DNA PCR was higher in the specimens with granulation or multinucleated giant cells in our study, although no statistical difference was observed. The sequencing results coincided with the PCR results. CONCLUSION: PCR can be used to determine MTB in ITB specimens. It is a rapid and convenient assay for the differential diagnosis of ITB and CD.%目的:评估聚合酶链反应(PCR)技术检测通过活检或手术获取的肠道组织石蜡标本中结核分枝 杆菌(Mycobacterium tuberculosis,MTB)DNA在鉴别克罗恩病(Crohn disease,CD)和肠结核(intestinal tuberculosis,ITB)中的可行性及价值.方法:根据来自MTB的重复插入序列IS6110设计引物,用PCR技术检测CD与ITB肠道组织蜡块标本中MTB DNA,利用基因直接测序法验证结果,分析PCR检测结果与病理特征间的关系.结果:ITB组MTB DNA检出率为32％,CD组MTB DNA检出率为0％,MTB DNA PCR法在ITB和CD鉴别诊断中的灵敏度为32％,显著高于抗酸染色(8％)和干酪样坏死(12％)(P＜0.05).MTB DNA PCR法在ITB和CD鉴别诊断中的特异度为100％,阳性预测值为100％,阴性预测值为59.5％.MTB DNA PCR阳性率在肉芽肿或多核巨细胞病理特征的标本中存在升高趋势,但差异无统计学意义.测序结果与PCR判读的结果相符.结论:PCR法用于MTBDNA检测,有助于ITB确诊,在ITB和CD的鉴别诊断中不失为一种方便快捷的病原学诊断方法.