Interleukin 8 Gene Polymorphisms Are Not Associated with Tuberculosis Susceptibility in the Chinese Population

Interleukin 8 （IL8） is an important chemokine that elicits host immune response against tuberculosis （TB）. However, whether there is an association between IL8 gene polymorphism and TB susceptibility in the Chinese population is unknown. IL8 gene was amplified and sequenced to search for nucleotide polymorphisms among the Chinese population. Four single nucleotide polymorphisms （SNPs） were identified, selected, and analyzed in a cohort of 438 patients with TB and 536 healthy controls. Allelic, genotypic, and haplotypic analysis demonstrated that the distribution of the four IL8 SNPs between patients with TB and healthy controls was not significantly different （P〉0.05）. The four IL8 SNPs detected in this study were not associated with TB susceptibility in the Chinese population. Secretion of IL8 by peripheral blood cells was greatly stimulated upon exposure to Mycobacterium tuberculosis whole cell extract, but such enhanced secretion was not associated with the IL8 rs4073 alleles.

Screening of Serum Biomarkers for Distinguishing between Latent and Active Tuberculosis Using Proteome Microarray

Objective To identify potential serum biomarkers for distinguishing between latent tuberculosis infection（LTBI） and active tuberculosis（TB）. Methods A proteome microarray containing 4,262 antigens was used for screening serum biomarkers of 40 serum samples from patients with LTBI and active TB at the systems level. The interaction network and functional classification of differentially expressed antigens were analyzed using STRING 10.0 and the TB database, respectively. Enzyme-linked immunosorbent assays（ELISA） were used to validate candidate antigens further using 279 samples. The diagnostic performances of candidate antigens were evaluated by receiver operating characteristic curve（ROC） analysis. Both antigen combination and logistic regression analysis were used to improve diagnostic ability. Results Microarray results showed that levels of 152 Mycobacterium tuberculosis（Mtb）-antigenspecific IgG were significantly higher in active TB patients than in LTBI patients（P 〈 0.05）, and these differentially expressed antigens showed stronger associations with each other and were involved in various biological processes. Eleven candidate antigens were further validated using ELISA and showed consistent results in microarray analysis. ROC analysis showed that antigens Rv2031 c, Rv1408, and Rv2421 c had higher areas under the curve（AUCs） of 0.8520, 0.8152, and 0.7970, respectively. In addition, both antigen combination and logistic regression analysis improved the diagnostic ability. Conclusion Several antigens have the potential to serve as serum biomarkers for discrimination between LTBI and active TB.