Osteoarticular tuberculosis: in search of new biomarkers

Performance of adenosine deaminase in synovial fluid for the diagnosis of tuberculous arthritis: A systematic review and meta-analysis

OBJECTIVES

Adenosine deaminase (ADA) activity has shown good performance in diagnosing pleural, peritoneal, and meningeal tuberculosis. This meta-analysis aimed to evaluate the performance of measuring ADA activity in synovial fluid for the early diagnosis of joint tuberculosis.

METHODS

We searched published information in MEDLINE, Embase, Cochrane Library, Web of Science, and MedRxiv databases, as well as unpublished information in the American College of Rheumatology and European League Against Rheumatism for conference abstracts (2012-2021). We also scanned the reference lists of articles. Two reviewers independently applied the criteria for selection, assessed quality, and extracted data (PROSPERO number CRD42021284472).

RESULTS

Seven independent studies (N=305 subjects) that compared ADA activity in synovial fluid with a composite reference diagnostic method for tuberculosis were included. Overall, the risk of bias was judged low. Studies were classified as high quality (n=3; 148 subjects) and low quality (n=4; 157 subjects). Pooled sensitivity and specificity of ADA activity was 94% (95% confidence interval [CI], 0.89-98; I2=23%) and 88% (95% CI, 83-92; I2=83%), respectively. The random-effects model for pooled diagnostic Odds ratio was 67.1 (95%CI, 20.3-222.2; I2=30%). The receiver operating characteristic curve area was 0.96 (95% CI, 0.92-0.99). Meta-regression did not identify the quality of the study, country of publication, or the type of assay as a source of heterogeneity.

CONCLUSIONS

Measuring ADA activity in synovial fluid demonstrates good performance for the early diagnosis of joint tuberculosis.

Endometrial Cytokine Expression from Clinically Suspected Genital Tuberculosis Patients at Tertiary Care Hospitals in Dhaka

Objective

The objective of this study was to measure gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) expression in endometrial tissue and/or aspirate from suspected genital tuberculosis patients with ectopic pregnancy and infertility in Bangladesh.

Methodology

A total 78 women of clinically suspected genital tuberculosis patients were enrolled as study population. These patients underwent manual vaccum aspiration (MVA) procedure, and endometrial tissues and/or aspirates were collected. Ziehl -Neelsen staining (Z-N staining) and Lowen–Stein Jensen (L-J) culture were done to detect Mycobacterium. The study participants were categorized as genital tuberculosis positive cases, genital tuberculosis negative cases and presumptive for tuberculosis cases based on the case definition used in this study. TNF-α and IFN-γ were measured by ELISA. Statistical analysis was done using SPSS (version-22).

Results

Out of 78 participants, pro-inflammatory cytokines IFN-γ and TNF-α were significantly increased in TB positive patients than TB negative patients (p < 0.05). IFN-γ value of TB positive patients (41.26 ± 41.05) was higher than TB negative (22.94 ± 44.51) patients. TNF-α value (44.31 ± 64.22) of TB positive patients was higher than TB negative (15.86 ± 41.45) patients. IFN-γ and TNF-α value of presumptive for tuberculosis cases were not statistically significant. According to ROC analysis, cut off value for IFN-γ was 23.5 and for TNF-α was 10 with highest sensitivity and specificity of 66.7%, 89.3%, and 66.7% and 73.1% respectively.

Conclusion

IFN-γ and TNF-α were significantly higher in TB positive patients and it may act as a potential biomarker for diagnosis of genital tuberculosis.

A systematic review of biomarkers to detect active tuberculosis

Millions of cases of tuberculosis (TB) go undiagnosed each year. Better diagnostic tools are urgently needed. Biomarker-based or multiple marker biosignature-based tests, ideally performed on blood or urine, for the detection of active TB might help to meet target product profiles proposed by the World Health Organization for point-of-care testing. We conducted a systematic review to summarize evidence on proposed biomarkers and biosignatures and evaluate their quality and level of evidence. We screened the titles and abstracts of 7,631 citations and included 443 publications that fulfilled the inclusion criteria and were published in 2010-2017. The types of biomarkers identified included antibodies, cytokines, metabolic activity markers, mycobacterial antigens and volatile organic compounds. Only 47% of studies reported a culture-based reference standard and diagnostic sensitivity and specificity. Forty-four biomarkers (4%) were identified in high-quality studies and met the target product profile minimum criteria, of which two have been incorporated into commercial assays. Of the 44 highest-quality biomarkers, 24 (55%) were multiple marker biosignatures. No meta-analyses were performed owing to between-study heterogeneity. In conclusion, TB biomarker discovery studies are often poorly designed and findings are rarely confirmed in independent studies. Few markers progress to a further developmental stage. More validation studies that consider the intended diagnostic use cases and apply rigorous design are needed. The extracted data from this review are currently being used by FIND as the foundation of a dynamic database in which biomarker data and developmental status will be presented.