Tuberculosis (TB) is a massive public health issue, with an estimated 10.4 million new cases each year globally, culminating in 1.8 million deaths. Current diagnostics rely on symptoms and sputum analysis. Sputum can be difficult to obtain from patients and poses a health risk to staff. The World Health Organisation has acknowledged the urgent need for additional tests to aid the early diagnosis of TB.

A diagnostic biomarker ideally needs to be specific, simple to sample and a reliable indicator of disease. Blood based diagnostics are easier to sample than sputum. Similarly, cytokines are already used as markers for different diseases. We evaluated the capacity of a 7 plasma protein profile (IL-6, IL-10, IP-10, MCP-1, sTNFR1, RANTES and VEGF) to distinguish between TB patients and healthy controls. Protein levels were measured in the plasma of 100 newly diagnosed TB patients in comparison to 100 healthy controls. 6 of these, all with known proinflammatory activity, were significantly elevated in the TB patients. The protein profile distinguished the two cohorts with an area under the curve of 0.883, a specificity of 82% and a sensitivity of 75%. Studies are ongoing to improve the sensitivity and specificity of this assay and test its reproducibility in additional cohorts.

This study demonstrates that a protein profile in plasma can be used to distinguish TB patients from healthy controls and has potential as a new biomarker to aid TB diagnosis.