Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 44 2 2015 02 15 185 93 Yongmei Yin The Fifth People's Hospital of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China AND The Hospital for Infectious Diseases of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China. Jie Qin The Mental Health Center of Wuxi, Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China. Yaping Dai The Fifth People's Hospital of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China AND The Hospital for Infectious Diseases of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China. Fanwei Zeng Dept. of Basic Medical Sciences, Medical College, Xiamen University, Xiamen, Fujian, China. Hao Pei The Fifth People's Hospital of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China AND The Hospital for Infectious Diseases of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China. Jun Wang The Fifth People's Hospital of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China AND The Hospital for Infectious Diseases of Wuxi, Affiliated to Jiangnan University, Wuxi, Jiangsu, China. 2015 10 14 Background: The ratio of CD4+/CD8+ has been used as a clinically index to evaluate patients’ immunity. Numerous researchers have studied CD4+/CD8+ ratio in pulmonary tuberculosis (PTB) patients. However, the change of CD4+/CD8+ ratio remains controversial. We present a meta-analysis of 15 case-control studies to identify the change of CD4+/CD8+ ratio in PTB patients. Methods: We assessed heterogeneity of effect estimates within each group using I2 test. Subgroup analysis was performed to explore the potential source of heterogeneity. To investigate further the potential publication bias, we visually examined the funnel plots. For robustness of results, we performed sensitivity analysis by removing studies. Data entry and analyses were carried out with RevMan 5.2 (The Nordic Cochrane Centre). Results: Twelve peripheral blood studies were categorized into two subgroups. Eight studies presented a significant decrease of CD4+/CD8+ ratio in PTB cases compared to healthy subjects (SMD: -0.45; 95% CI -0.65–-0.25; I2 = 7%). Other four studies researched on the newly diagnosed patients presented a more seriously and significantly decrease (SMD: -2.17; 95% CI -2.61–-1.74; I2 = 37%). The pooled analysis of bronchoalveolar lavage fluid (BALF) studies showed a significant increase of CD4+/CD8+ ratio using Flow Cytometry (FCM) (SMD: 4.75; 95% CI 3.44–6.05; I 2 =0%). Conclusion: The present meta-analysis indicated that there was a synthetic evidence for the reduced CD4+/CD8+ ratio in peripheral blood of PTB patients, especially newly diagnosed cases. However, the CD4+/CD8+ ratio in BALF was increased using method of FCM. https://ijph.tums.ac.ir/index.php/ijph/article/view/3698 https://ijph.tums.ac.ir/index.php/ijph/article/download/3698/3372