When people fall ill, their immune cells respond by switching genes on and off, producing RNA markers detectable in the blood. Scientists have known these patterns can help identify the cause of an illness — distinguishing, for example, a bacterial from a viral infection. But the international team behind VeloCD, led by researchers at Imperial College London in the UK, wanted to go further: could blood RNA also predict where an illness is heading?
The answer, at least in early testing, appears to be yes. VeloCD adapts a bioinformatics technique called RNA velocity — originally developed for single-cell analysis — and applies it to whole-blood samples. By measuring not just which genes are active, but whether their activity is increasing or decreasing, the method can infer whether a patient is on a trajectory toward recovery or deterioration.
In a proof-of-concept study, the team successfully predicted whether children with acute fever were likely to recover or worsen. They also predicted whether healthy adults exposed to influenza or COVID-19 viruses would go on to develop illness. In further tests, VeloCD demonstrated potential as a tool to flag complications of HIV and tuberculosis — and to predict, after just a single dose of therapy, how well patients with inflammatory bowel disease would respond to treatment.
Professor Aubrey Cunnington, Head of the Department of Infectious Disease at Imperial College London, leads the research. The team has filed a patent and made the VeloCD tool publicly available online for researchers to use. A clinical test, they believe, could be ready within five years. The hope is that one day, hospitals could use it to rapidly identify who needs urgent care — and who can safely be sent home.