Abstract:

Objective To evaluate the clinical value of immunohistochemistry (IHC) and polymerase chain reaction (PCR) methods in pathological diagnosis of tuberculous lymphadenitis. Methods Paraffin-embedded tissue specimens from 48 patients with tuberculous lymphadenitis who had undergone radical resection (the tuberculosis (TB) group) and 21 cases with other diseases in lymph node (the non-TB group) were collected during Jan 2012 to Jul 2013 in Beijing Chest Hospital, Capital Medical University. One-step IHC using antibody targeting Ag85B, Taqman fluorescent quantitative PCR and acid-fast staining were conducted. Their diagnostic efficiency were analyzed, taking the clinical final diagnosis as golden standard.Results The IHC and PCR showed significantly higher sensitivity than that of acid-fast staining (χ ²=6.27, P=0.012; χ ²=10.84, P=0.001, respectively), by the results of 52.1% (25/48) and 60.4% (29/48) versus 27.1% (13/48). However, there was no significant difference in sensitivity between IHC and PCR (χ ²=0.68, P=0.411). The detection results of IHC, PCR and acid-fast staining in non-TB group were all negative, with a specificity of 100% (21/21) for each test. The IHC and PCR had higher negative predictive value and accordance rate than acid-fast staining (47.7% (21/44), 52.5% (21/40), 37.5% (21/56), respectively; 66.7% (46/69), 72.5% (50/69), 49.3% (34/69), respectively). Conclusion IHC and PCR methods are simple and have higher sensitivity compared to acid-fast staining method. IHC and PCR showed good clinical application value in pathological diagnosis of tuberculous lymphadenitis.

Key words: Tuberculosis,lymph node, Immunohistochemistry, Polymerase chain reaction, Pathology, Comparative study