The Journal of Heart and Lung Transplantation
International Society for Heart and Lung Transplantation.
(153)| Volume 41, ISSUE 4, SUPPLEMENT , S75-S76, April 2022

Metagenomic Next Generation Sequencing (mNGS) Can Complement Fractional Donor-Derived Cell-Free DNA in Lung Allograft Assessment: Pilot Data


      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.
      Tabled 1
      Characteristics from LT Patients with Clinically Significant vDNA/RNA Signatures from mNGS Testing
      PatientTime post-LT (d)Histology (ISHLT)Clinical DiagnosisRVP PCRDNA and RNA Virus by mNGSdd-cfDNA (%)
      62F76A0BXINFXNNegative, Staph aureusInfluenza A1.24
      70F199A0B0STABLENegativeInfluenza B1.19
      29F188A0BXSTABLENegativeInfluenza B1.96