Cytomegalovirus immunity in high-risk liver transplant recipients following preemptive antiviral therapy vs. prophylaxis.

ABSTRACT

Cytomegalovirus (CMV)-specific T-cells, NK cells, and neutralizing antibodies (nAb) were assessed in a randomized trial of CMV prevention with preemptive antiviral therapy (PET) vs. prophylactic antiviral therapy (PRO) in donor seropositive/recipient seronegative (D+R-) liver transplant recipients (LTxR), at 100 days (end of intervention), and at 6 and 12 months post-transplant. The PET group had significantly increased numbers of circulating polyfunctional T-cells, NK cells, and nAb compared to the PRO group at day 100 and several CMV immune parameters remained significantly higher by 12 months post-transplant. Among PET recipients, preceding CMV viremia (vs. no preceding viremia) was associated with significantly higher levels of most CMV immune parameters at day 100. Higher numbers of CMV-specific polyfunctional T-cells and NKG2C+ NK cells at day 100 were associated with a decreased incidence of CMV disease in multivariable Cox regression. The strongest associations with protection against CMV disease were with increased numbers of CMV-specific polyfunctional CD4 T-cells, CD3negCD56dimCD57negNKG2Cpos, and CD3negCD56dimCD57posNKG2Cpos NK cells. PET is superior to PRO for CMV disease prevention by allowing low-level CMV replication and associated antigen exposure that is promptly controlled by antiviral therapy and facilitates enhanced CMV protective immunity in D+R- LTxR.