TABLE 1.
Studies that evaluated the association between TTV load and allograft rejection in kidney transplant recipients
| Study designa | TX period | Included patients | Endpoint; timing | Total BX; BX proven rejection | PCR | Main association | Limitationsb |
|---|---|---|---|---|---|---|---|
| Cohort74 | 2014–2016 | 221 | Clinically overt rejection; <3 mo post-TX | 10c | C | TTV at TX–rejection | Secondary endpoint; BX not mandatory; multiple testing; missing information on model design/some major determinants of TTV not included |
| Cohort75 | 2016–2018 | 37 | Rejection (iBX); months 4–12 post-TX | 39; 11 | IH | TTV 2 wk before BX–TCMR, AMR, mixed | Limited number of events |
| Cohort76 | 2016–2018 | 82 | Rejection (pBX); month 12 post-TX | 82; 19 | IH | TTV at BX–TCMR, AMR | High loss to follow-up |
| Cross-sectional77 | 1973–2014 | 715 | Rejection (pBX); 6 y post-TX | 86; 46 | IH | TTV at BX–AMR | Cross-sectional design; possible selection bias due to missing BX in DSA-positive subjects |
| Case-control78 | 2012–2017 | 113 | Rejection (iBX); months 4–12 post-TX | 113; 33 | IH | TTV 1 mo before BX–TCMR, AMR | Case-control design |
| Case-control79 | 2012–2014 | 63 | Rejection (iBX); <2 y post-TX | 12d | C | TTV pre-TX–TCMR, AMR, mixed | Possible selection bias; nonrejection not BX proven; multiple testing; no effect size adjustment |
| Case-control21 | 2003–2013 | 389 | Clinically overt rejection; <12 mo post-TX | 80; 54e | IH | TTV kinetic–time to rejection | Secondary endpoint; BX not mandatory; possible misclassification of rejection: nonrejection in BX categorized as rejection |
The studies are listed according to the design and date of their online publication.
All studies followed a noninterventional and single-center design.
The total number of biopsies was not stated; 11 events were scored as rejection.
The total number of biopsies was not stated; 14 biopsies were available for the posttransplant month 1 evaluation.
Eighty-eight events were scored as rejection.
AMR, antibody-mediated rejection; BX, biopsy; C, commercial; DSA, donor-specific antibody; iBX, indication biopsy; IH, in-house; pBX, protocol biopsy; PCR, polymerase chain reaction; TCMR, T cell–mediated rejection; TTV, torque teno virus; TX transplantation.