Biosignatures fingerprint tuberculosis and sarcoidosis

Tuberculosis and sarcoidosis are both serious lung diseases, but their similar symptoms mean that it can be hard to tell them apart. Finding a panel of biomarkers will improve diagnosis and help doctors direct care appropriately, and research at the Max Planck Institute for Infection Biology in Germany has brought this a step closer.

There is no single marker that can be used to tell tuberculosis and sarcoidosis apart, and differentiating the two diseases is important because sarcoidosis is not contagious and many cases do not need treatment, whereas tuberculosis is a bacterial infection and can be treated with a course of antibiotics.

To create a panel of biomarkers, also known as a biosignature, researchers profiled genes and microRNA (miRNA) in whole blood from people with tuberculosis and sarcoidosis, and analyzed inflammatory markers in their blood plasma. They found that the profiles of genes and miRNAs were similar; however, 700 genes and four miRNAs could be used to mark the difference between the two diseases. There were more inflammatory and antimicrobial markers in the tuberculosis patients than in the sarcoidosis patients, and 12 of these could help to distinguish between the two diseases.

The process the researchers used to find this biosignature could be used to create panels of biomarkers to distinguish between other diseases: for example HIV/AIDS, tuberculosis and malaria, according to Stefan Kaufmann from the Max Planck Institute for Infection Biology. "We should first of all distinguish between healthy and diseased individuals and then separate the individual diseases from one another in the next steps. We can then unequivocally identify a disease using a handful of genes per step."

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