SLC11A1 Polymorphisms and TB Figure 4. Meta-analysis of the association between tuberculosis and SLC11A1 INT4 polymorphism (*C vs. GG). c = subgroup of patients who were aboriginal Taiwanese; d = subgroup of patients who were Hans; CI = confidence interval; OR = odds ratio. doi:10.1371/journal.pone.0015831.g004 number of studies in the stratified analysis and heterogeneity between studies might explain, at least in part, the existing inconsistency. TB is a serious public health problem in worldwide. Early diagnosis, drug resistance, vaccine and HIV co-infection are major factors influencing efficiency of TB prevention and control [44]. In the past decades, the association between host genetic polymorphisms and TB susceptibility has been widely studied as well. Most of the target loci were localized in genes participating immune response [45]. The NRAMP1 protein is an integral membrane protein expressed exclusively in the lysosomal compartment of monocytes and macrophages [3]. It has been reported that NRAMP1 regulates macrophage activation and is associated with TB susceptibility. Underlying mechanisms have been proposed based on its function as metal transporter [46]. After phagocytosis, NRAMP1 is targeted to the membrane of the microbe-containing phagosome, where it mediates transport of iron and other cations. Iron is essential for biological functions, both for host immune defense and mycobacterial growth. Therefore, NRAMP1 has also been suggested to play a role in determining host susceptibility to other intracellular pathogens and autoimmune diseases [47]. Positive association between SLC11A1 polymorphisms and these infections and diseases has provided strong evidence for this hypothesis. In 2006, Li HT and colleagues reported a meta-analysis on SLC11A1 polymorphisms and TB which based on 14 eligible studies published until December 2004 [8]. In this article, less common alleles at the four most widely studied loci were generally PLoS ONE | www.plosone.org 5 January 2011 | Volume 6 | Issue 1 | e15831