Tuberculosis diagnosis: algorithm that May discriminate latent from active tuberculosis.

Diagnosis of tuberculosis still faces a lot of challenges and is one of the priorities in the field of tuberculosis management. Deciphering the complex tuberculosis pathogenicity network could provide biomarkers for diagnosis. We discussed the distribution of HLA-B17, -DQB and -DRB together with QuantiFERON test results in tuberculosis infection. A case control study was done during which a total of 337 subjects were enrolled comprising 227 active tuberculosis (ATB), 46 latent tuberculosis infection (LTBI) and 64 healthy controls (HC). Sequence-specific primer polymerase chain reaction and immune epitope database were used to genotype samples and determine the epitope binding ability of the over-represented alleles respectively. QuantiFERON test was done according to manufacturer's instructions. The peptides HLA-B*5801 and HLA-DRB1*12 and the peptides HLA-B*5802 and HLA-DQB1*03 were found to be associated with latent tuberculosis while the haplotypes DRB1*10-DQB1*02 and DRB1*13-DQB1*06 were found to be associated with active tuberculosis (All p-values≤0.05). The association of HLA-B*5801 and HLA-B*5802 with latent tuberculosis was linked to their ability to bind or not mycobacterial antigens. DRB1*10-DQB1*02 haplotype was found to be over-represented in LTBI compared to ATB (p-value = 0.0015) while DRB1*13-DQB1*06 was found to be under-represented in LTBI compared to ATB (p-value = 0.0335). The DRB1*10-DQB1*02 haplotype was only found in the LTBI when compared with the ATB group. The present study suggests the following algorithm to discriminate LTBI from ATB: QuantiFERON+ and DRB1*10-DQB1*02 haplotype + may indicate LTBI; QuantiFERON+ and DRB1*10-DQB1*02 haplotype - may indicate ATB.

MicroRNA hsa-miR-29a-3p is a plasma biomarker for the differential diagnosis and monitoring of tuberculosis.

The diagnosis of tuberculosis (TB) continues to pose substantial public health problems. The quest for diagnostic biomarkers for TB is therefore primordial. This study aimed to evaluate the diagnostic and anti-TB treatment monitoring potentials of some selected miRNAs. Quantitative real time polymerase chain reaction and Receiver operating characteristics were used to estimate the ability of miRNAs to discriminate between healthy controls (HEC), latent (LTB) and active TB (ATB). The study showed that: hsa-miR-29a-3p, hsa-miR-155-5p and hsa-miR-361-5p were significantly upregulated in ATB compared to HEC while hsa-miR-29a-3p, and hsa-miR-361-5p were also significantly up-regulated in ATB compared to LTB (all P ≤ 0.05). MiR-29a-3p showed a good (81.37%) distinguishing performance in discriminating ATB from HEC and a good (84.35%) diagnostic performance in discriminating ATB from LTB. The performance of miR-29a-3p present in the blood in discriminating active TB from latent TB and healthy controls indicates it may be a useful biomarker for diagnosis of TB. Because this miRNA is found in blood (plasma) which is easy to collect compared to sputum it could be used in pediatric and extra-pulmonary TB cases.