RNA signatures could be used for TB diagnostic test

A set of RNA transcriptional signatures expressed in suspected tuberculosis patients could lead to a new diagnostic test to distinguish active and latent disease, according to a study recently published in PLOS Medicine.

An international research team led by Michael Levin from Imperial College London attempted to identify a host blood RNA transcriptional signature that could be used in a simple diagnostic test. TB diagnosis is an ongoing challenge because the signs and symptoms of the disease may be similar to the symptoms of other diseases. Additionally, current TB diagnostics have significant limitations.

The researchers took blood samples from 584 adult patients with suspected TB in South Africa and Malawi who were diagnosed with either TB, latent TB infection or another disease. The team analyzed the patients' blood transcriptional profiles to find signatures that could be used to differentiate TB from other conditions.

Using the RNA transcriptional signatures, the disease risk score was found to be 95 percent sensitive and 90 percent specific when attempting to distinguish TB from latent TB in test cohorts. The tests also found 93 percent sensitivity and 88 percent specificity when distinguishing TB from other diseases. An independent validation cohort found similar results.

"From a clinical perspective a simple transcriptome-based test that reliably diagnoses or excludes TB in the majority of patients undergoing investigation for suspected TB, using a single blood sample, would be of great value, allowing scarce hospital resources to be focused on the small proportion of patients where the result was indeterminate," the researchers said. "The challenge for the academic research community and for industry is to develop innovative methods to translate multi-transcript signatures into simple, cheap tests for TB suitable for use in African health facilities."

According to the World Health Organization, approximately 1.4 million died as a result of TB in 2011.