Tuberculosis (TB) is a chronic infectious disease that has been threatening public health for many centuries. The clinical diagnostic procedure for TB is time-consuming and laborious. In the last 20 years, real-time fluorescence-based quantitative PCR (real-time PCR) has become a better alternative for TB diagnosis in clinics due to its sensitivity and specificity. Recently, digital droplet PCR (ddPCR) has been developed, and it might be an ideal alternative to conventional real-time PCR for microorganism detection. In this study, we aimed to assess the capacity of ddPCR and real-time PCR for detecting low levels of circulating Mycobacterium tuberculosis (MTB) DNA. The study involved testing whole blood samples for an MTB DNA target (known as IS6110). Blood samples were obtained from 28 patients with pulmonary TB, 28 patients with extrapulmonary TB, and 28 healthy individuals. The results show that ddPCR could be used to measure low levels of MTB DNA, and it has the potential to be used to diagnose pulmonary and extrapulmonary TB based on clinical samples.

This study was to investigate the relationship between IL-18-137G/C polymorphism and TB risk by meta-analysis. The literatures about the IL-18-137G/C polymorphism and risk of tuberculosis were selected from four English databases and four Chinese databases. Data were extracted from the studies by two independent reviewers. Statistical analysis was executed using Revman 5.3 and Stata 11.0 software. A total of 5 studies with 558 TB patient and 720 controls were included in this meta-analysis, The results showed that-137G/C polymorphisms in the IL-18 gene were associated with TB risk in china when taking comparisons of the G allele vs. C allele (OR=1.49, 95% CI=1.21-1.84, P=0.0002), GG vs. GC+X.06, P=0.0003). It was also significant in the subgroup analysis of Chinese adults (G allele vs. C allele: OR=1.32, 95%=CI 1.03-1.70, P=0.003; GG vs. GC+CC: OR=1.39, 95% CI=1.01-1.91, P=0.04) and Chinese children (G allele vs. C allele: OR=1.91, 95% CI=1.31-2.78, P=0.0008; GG vs. GC+CC: OR=2.02, 95% CI=1.33-3.07, P=0.0010). This study provides the evidence that the allele G of IL-18-137G/C polymorphism was closely associated with TB risk in China.