Viral reactivations (VRs) after hematopoietic cell transplantation (HCT) contribute to significant morbidity and mortality. Timely immune reconstitution (IR) is suggested to prevent VR.Objectives:
We studied the relation between IR (as a continuous predictor over time) and VR (as a time-varying predictor) and the relation between VR and other clinical outcomes.Methods:
In this retrospective analysis all patients receiving a first HCT between January 2004 and September 2014 were included. IR (CD3/CD4/CD8 T, natural killer, and B cells) was measured biweekly until 12 weeks and monthly thereafter. Main outcomes of interest were VR of adenovirus, EBV, human herpesvirus 6 (HHV6), cytomegalovirus (CMV), and BK virus screened weekly. Clinical outcomes included overall survival (OS), event-free-survival, nonrelapse mortality (NRM), and graft-versus-host disease. Cox proportional hazard and Fine and Gray competing risk models were used.Results:
Two hundred seventy-three patients (age, 0.1–22.7 years; median follow-up, 58 months) were included. Delayed CD4 reconstitution predicted reactivation of adenovirus (hazard ratio [HR], 0.995;P= .022), EBV (HR, 0.994;P= .029), and HHV6 (HR, 0.991;P= .012) but not CMV (P= .31) and BK virus (P= .27). Duration of adenovirus reactivation was shorter with timely CD4 reconstitution, which was defined as 50 × 106 cells/L or greater within 100 days. Adenovirus reactivation predicted lower OS (HR, 2.17;P= .0039) and higher NRM (HR, 2.96;P= .0008). Concomitant CD4 reconstitution abolished this negative effect of adenovirus reactivation (OS,P= .67; NRM,P= .64). EBV and HHV6 reactivations were predictors for the occurrence of graft-versus-host disease, whereas CMV and BK virus reactivation did not predict clinical outcomes.Conclusion:
These results stress the importance of timely CD4 reconstitution. Strategies to improve CD4 reconstitution can improve HCT outcomes, including survival, and reduce the need for toxic antiviral therapies.