Quantification of Torque Teno Virus and Epstein-Barr Virus Is of Limited Value for Predicting the Net State of Immunosuppression After Lung Transplantation

Nordén, Rickard; Magnusson, Jesper; Lundin, Anna; Tang, Ka-Wei; Nilsson, Staffan; Lindh, Magnus; Andersson, Lars-Magnus; Riise, Gerdt C; Westin, Johan

A majority of the patients had detectable TTV-DNA levels before transplantation (pre-LTx), and the levels subsequently increased until a peak was reached at 3 months post-LTx, after which the levels gradually decreased (Figure 1 ). The mean TTV-DNA levels for the respective time periods were 6.7 log10 1-3 months post-LTx, 6.4 log10 3-6 months post-LTx, 5.8 log10 6-12 months post-LTx, and 5.2 log10 12-24 months post-LTx, respectively. Conversely, a majority of the patients had no detectable EBV-DNA prior to transplantation as determined in serum. At 1 month post-LTx, a peak in mean EBV-DNA levels was observed, which decreased already 2 months post-LTx and thereafter remained at a relatively constant level, determined in whole blood (Figure 1 ). The mean EBV-DNA levels for the respective time periods were 2.7 log10 1-3 months post-LTx, 2.6 log10 3-6 months post-LTx, 2.6 log10 6-12 months post-LTx, and 2.7 log10 12-24 months post-LTx, respectively. Overall, fewer patients had detectable levels of EBV-DNA compared with TTV-DNA ( Figure 1 ). Although the individual TTV-DNA levels varied, a majority of the patients had detectable levels across the entire FU period. In comparison, only a minority of the patients had detectable levels of EBV-DNA over a longer consecutive period, and a large fraction had EBV-DNA levels below the level of quantification (LOQ) at any given time point during FU (Figure 1 ). Three patients developed suspected PTLD. No case was biopsy-verified, and all were reversed upon modification of immunosuppression. Detailed individual TTVand EBV-DNA level kinetics for each patient, including information regarding all infectious events and acute rejections, are displayed in Supplementary Figure 1 .