Tuberculosis caused by Mycobacterium tuberculosis (Mtb) infection remains a large global public health problem. One striking characteristic of Mtb is its ability to adapt to hypoxia and trigger the...

Background: Anemia is one of the risk factors for tuberculosis (TB), and more than 90% of TB patients suffer from anemia. The majority tuberculosis patients who had poor prognosis experienced anemia during the course of treatment. The objective of our study is to analyse the influences of anemia on the prognosis of tuberculosis patients in terms of pulmonary M. tuberculosis loads, lung pathology, and clinical factors. Methods: In this retrospective cohort study, 155 TB patients in Shanghai were divided into the anemia-tuberculosis (A-TB) group and non-anemia-tuberculosis (NA-TB) group. We analysed bacteria counts in sputum smear and sputum smear conversion time between two groups. We evaluated the pulmonary pathology of cavity and effusion in A-TB patients. Logistic regression analysis was performed to explore the potential correlations of anemia with sputum bacterial load and pulmonary pathology. We compared clinical factors including the immune factors and inflammatory cells. Results: Compared with the NA-TB (n=89) group, the A-TB group (n=66) had poorer improvement of lung injury in terms of cavity closure (4.7±3.59 vs. 10.56±7.42; P=0.036) and fluid improvement [4 (30.77%) vs. 12 (92.31%); P=0.001] during conventional treatment. At the start of treatment, the immune factors complement 4 (C4) [0.25 (0.19, 0.295) vs. 0.3086±0.076; P=0.006] and C-reactive protein (CRP) [3.2 (3.2, 21.5) vs. 19.5 (6.25, 78.35); P=0.016] were significantly higher in A-TB with NA-TB. During the course of treatment, the gradual decrease in the absolute number of lymphocytes (LYM#) (P=0.0012, r=−0.3400) and the gradual increase in the absolute number of monocytes (MONO#) (P=0.0050, r=0.2968), the absolute number of basophils (BASO#) (P=0.0213, r=0.2451), the red blood cell distribution width-coefficient (RDW-CV) (P=0.0136, r=0.2651), suggesting poor prognosis in anemic TB patients. Conclusions: Anemia is a risk factor for lung injury in TB patients. Inflammatory factors and inflammatory cells are increased during treatment in A-TB patients.

Background: Presently, tuberculosis (TB) poses a global threat to human health. The development of reliable laboratory tools is vital to the diagnosis and treatment of TB. MPT64, a protein secreted by Mycobacterium tuberculosis complex, is highly specific for TB, making antibody to MPT64 a reagent specific for the diagnosis of TB. Method: Antibody to MPT64 was obtained by a combination of genetic engineering and immunization by the system evolution of ligands by exponential enrichment. A high-affinity aptamer of antibody to MPT64 was selected from a random single-stranded DNA library, and a sandwich ELISA method based on this aptamer was developed. This ELISA method was used to detect TB in 328 serum samples, 160 from patients with pulmonary TB (PTB) and 168 from non-tuberculous controls. Results: The minimum limit of detection of the ELISA method was 2.5 mg/L, and its linear range varied from 10 mg/L to 800 mg/L. Its sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and area under the curve, with 95 % confidence intervals, were 64.4 % (56.7 %–71.4 %), 99.4 % (96.7 %–99.9 %), 108.2 (15.3–765.9), 0.350 (0.291–0.442) and 0.819 (0.770–0.868), respectively. No significant difference in sensitivity was observed between sputum smear positive (73/112, 65.2 %) and negative (30/48, 62.5 %) individuals. Conclusions: This sandwich ELISA based on an MPT64 antibody aptamer may be useful for the serological diagnosis of PTB, both in sputum smear positive and negative patients.

Background: The mycobacterial genome is inclined to polymerase slippage and a high mutation rate in microsatellite regions due to high GC content and absence of a mismatch repair system. However, the exact molecular mechanisms underlying microsatellite variation have not been fully elucidated. Here, we investigated mutation events in the hyper-variable trinucleotide microsatellite locus MML0050 located in the Rv0050 gene of W-Beijing and non-W-Beijing Mycobacterium tuberculosis strains in order to gain insight into the genomic structure and activity of repeated regions. Results: Size analysis indicated the presence of five alleles that differed in length by three base pairs. Moreover, nucleotide gains occurred more frequently than loses in this trinucleotide microsatellite. Mutation frequency was not completely related with the total length, though the relative frequency in the longest allele was remarkably higher than that in the shortest. Sequence analysis was able to detect seven alleles and revealed that point mutations enhanced the level of locus variation. Introduction of an interruptive motif correlated with the total allele length and genetic lineage, rather than the length of the longest stretch of perfect repeats. Finally, the level of locus variation was drastically different between the two genetic lineages. Conclusion: The Rv0050 locus encodes the bifunctional penicillin-binding protein ponA1 and is essential to mycobacterial survival. Our investigations of this particularly dynamic genomic region provide insights into the overall mode of microsatellite evolution. Specifically, replication slippage was implicated in the mutational process of this microsatellite and a sequence-based genetic analysis was necessary to determine that point mutation events acted to maintain microsatellite size integrity while providing genomic diversity.

Background: Anemia leads to a lower cure rate and poor prognosis in tuberculosis patients. Effective predictors for the prognosis of tuberculosis with anemia (A-TB) are urgently needed. Monocyte has been proven to be a prognostic biomarker of many lung diseases. Whether monocyte that the predominant innate immune cell as early defense against tuberculosis can predict A-TB is not known.Methods: Data for A-TB patients with initial treatment in Shanghai Pulmonary Hospital were retrospectively collected and analyzed. Logistics regression analysis was used to study the correlation between peripheral blood cells and treatment outcomes. The receiver operating characteristic (ROC) curve was used to determine the cut-off value. We estimated a 12-month prognosis using Kaplan–Meier techniques. The Cox proportional hazards model was used for the univariate and multivariate analyses to analyze the predictors of poor prognosis of A-TB.Results: Of 181 patients analyzed, 94 were cured and 87 non-cured. Logistic regression analysis identified monocyte as an independent immune-related risk factor for the prognosis of A-TB (OR: 7.881, 95% CI: 1.675–37.075, P = 0.009). The ROC curve analysis proved that the most discriminative cut-off value of monocyte was 0.535 × 10^9/L. K–M analysis demonstrated that the cumulative cure rates of A-TB were significantly higher in A-TB with monocyte < 0.535 × 10^9/L (69.62%) than that in those with monocyte ≥ 0.535 × 10^9/L (38.24%) (Log-rank, χ² = 16.530, P < 0.0001). On univariate and multivariable analysis, monocyte was an independent predictor of poor prognosis in A-TB. Similarly, monocyte was also an independent predictor of poor pulmonary cavity closure in A-TB (HR: 3.614, 95% CI: 1.335–9.787, P = 0.011).Conclusion: In A-TB patients, elevated monocyte was associated with poor prognosis and poor cavity pulmonary closure. Monocyte may provide a simple and inexpensive prognostic biomarker in A-TB.