Torque teno virus kinetics after lung transplantation and its association to immunosuppression schemes and to clinical complications

Abstract

Background: We have shown previously that the plasma DNA level of human Torque Teno virus (TTV), a virus which is widespread in the population and causes persistent DNAemia in the absence of any defined disease, is associated with immunosuppression in lung transplant recipients (LTRs). We now investigated the correlation of TTV DNA with different immunosuppressive schemes, and with the occurrence of clinical complications. Methods: Plasma TTV-DNA loads were analyzed at defined intervals within one year post transplantation by quantitative real-time PCR in 44 LTRs, receiving induction therapy with either Alemtuzumab (Campath) (n=26) or with ATG (n=12) or received no induction therapy (n=6). The TTV load was further compared to clinical data. Results: The TTV-DNA load significantly increased in all cases post transplantation within the first 60-90 days and remained at high levels thereafter. The TTV-DNA load reached significantly higher levels in patients receiving induction therapy with Campath (p<0.001). In 25 patients episodes of microbial infections occurred within the first year after transplantation. Thepatients' mean TTV DNA load prior to these episodes was significantly higher than that in 19 control patients without infections at the same time period (p=0.002). Conclusions: Induction therapy with Campath seems to result in higher immunosuppression, reflected by TTV-DNA load post transplantation. Furthermore, it was confirmed that high plasma TTV- DNA load is related to the development of microbial infections.