Researchers from Stanford University successfully used circulating cell-free DNA (cfDNA) to identify infections in lung transplants that can often be found only with a more invasive transbronchial biopsy. The investigators quantified cell-free donor-specific DNA (cfdDNA) in the plasma of transplant recipients to measure rates of infection and rejection. Infections were identified by comparing nonhuman cfDNA with known genomic databases of pathogens.
This hypothesis free approach led to find HHV-6 & 7 at high levels in patients with infections, even though these viruses are not generally considered lung pathogens.
With only a median survival of 5.3 years, lung transplantation is associated with poor clinical outcomes. Complications are common, and it is difficult to distinguish between post-transplantation infection and rejection, as patients often present with similar symptoms.
Circulating cell free DNA contains 10 to 100 billion fragments per milliliter of plasma, representing a wealth of information about the patient’s health. This approach holds promise for identifying infections such as HHV-6 that are often not detectable in the plasma using standard quantitative PCR testing.
For more information, read the full paper: De Vlaminck 2015