ABSTRACT
Donor derived cell free DNA (ddcfDNA) is a noninvasive blood test used to assess the risk of allograft rejection in both lung and heart transplant recipients. The normal value for lung transplant recipients with a quiescent graft is <0.5%, while that for heart transplant recipients is <0.12%. There is no data on the expected normal level for combined organ transplants including heart and lung transplants. Here we present longitudinal ddcfDNA data on two combined heart/lung transplant recipients. Immunosuppression regimens for both consisted of prednisone, tacrolimus, and mycophenolate after basiliximab for induction. Patient 1 is a 25 year old female who received combined bilateral lung and heart transplant for primary ciliary dyskinesia and severe MR. Her 1 month ddcfDNA level was 2.1%, which correlated with A4 cellular rejection. Her 2 month ddcfDNA level was 1% and then was under the 0.5% from 3 months onward. She has not had any further cellular or AMR. Cardiac allograft function has been normal on serial echos. Patient 2 is a 35 year old female who received combined bilateral lung and heart transplant for scleroderma related ILD with PAH. Her 1 month ddcfDNA level was 2%, with A3 cellular rejection. Her ddcfDNA level at 2 months was 1.2%, she had DSA that was treated. Her 3 month level was 0.84%, at which time she had a non-covid coronavirus. Since month 4 her ddcfDNA has remained under 0.5% and she has not had any recurrent cellular or AMR. Cardiac allograft function was initially normal, declined to mildly impaired at 2 months, has since recovered and remains normal on serial echos. ddcfDNA is a useful tool for assessing allograft dysfunction in both lung and heart transplant recipients. It is conceivable that due to the size and immunogenicity of the lung allograft, there is little increase in ddcfDNA in these recipients above that of isolated lung transplant recipients. Our experience with these two recipients does attest to this theory. However, larger studies are necessary to evaluate this further. [ABSTRACT FROM AUTHOR] Copyright of Journal of Heart & Lung Transplantation is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)