Transbronchial biopsy (TBBx) histology and lavage (BAL) for microbiology are standard of care in lung transplant (LT) evaluation, but are inherently flawed. Plasma donor-derived cell-free DNA (dd-cfDNA) and viral DNA/RNA (vDNA/RNA) are promising biomarkers for more accurate assessment of allograft injury. Here we compare TBBx histology, BAL microbiology, dd-cfDNA and vDNA/RNA in matched samples.
40 post-LT samples (median 212 days) from 33 patients (median age: 61.0 yrs) were analyzed for dd-cfDNA fraction (Prospera™, Natera) and vDNA/RNA by metagenomic next-generation sequencing (mNGS) (Galileo™-ONE ArcBio) and correlated with clinical-pathologic (TBBx) diagnosis and BAL microbiology including Respiratory Viral Panel (RVP) multiplex PCR testing (BioFire RP2.1™; Biomerieux)
Native lung diseases included: IPF (N=18), COPD (N=17), CF (N=2) and PAH (N=3). mNGS identified vDNA/RNA considered pathologic to LT in 27.5% (11/40) cases, including 2 previously undiagnosed cases of HIV-1, with a median dd-cfDNA of 1.14% [TABLE]. For 9 cases with “negative” BAL/RVP, putative respiratory viral infection was indicated by mNGS. vDNA/RNA was also detected in 3 cases of histologic acute cellular rejection (ACR), one of which had elevated dd-cfDNA. In 2/4 patients with chronic lung allograft dysfunction (CLAD), the dd-cfDNA fraction was elevated and associated with vDNA/RNA. Two stable patients (A0B0/X) with vDNA/RNA had elevated dd-cfDNA.
Detection of clinically significant vDNA/RNA signatures by plasma mNGS testing contradicted clinical-pathologic diagnoses in >25% of patients. Future studies will help better understand and adjudicate discrepant results between TBBx histology, BAL microbiology, dd-cfDNA and mNGS. mNGS testing offers promise for properly assigning clinical-pathologic diagnosis in the assessment of LT health and may support the appropriate adjudication of elevated dd-cfDNA fractions.
|Characteristics from LT Patients with Clinically Significant vDNA/RNA Signatures from mNGS Testing|
|Patient||Time post-LT (d)||Histology (ISHLT)||Clinical Diagnosis||RVP PCR||DNA and RNA Virus by mNGS||dd-cfDNA (%)|
|62F||76||A0BX||INFXN||Negative, Staph aureus||Influenza A||1.24|
© 2022 Published by Elsevier Inc.