Cytomegalovirus Viral Load Dynamics and Outcomes After Liver Transplantation in Moderate and Low Risk Patients Treated With Cytomegalovirus Immune Globulin Prophylaxis

Cytomegalovirus immune globulin (CMVIG) reduces severe Cytomegalovirus (CMV) associated disease in liver transplant recipients (LTR). Because CMV viral loads (VL) were not available when the original prophylaxis trial was conducted, we retrospectively assessed CMV disease severity and CMV VL patterns in moderate and low-risk LTR receiving CMVIG prophylaxis. CMV VLs were measured using a quantitative PCR assay (Eurofins Viracor) in stored serial serum specimens from 96 LTR (D-/R- and R +). CMV-associated disease was classified according to original trial definitions and stratified by CMV disease severity. CMV outcomes and VL parameters were compared between CMVIG and placebo groups. 96 patients out of the original 146 study subjects had available serum samples for analysis. 67 (70%) had at least 1 detectable CMV VL. Severe CMV disease (vs. CMV syndrome/asymptomatic CMV disease) was associated with higher peak CMV VLs (p < 0.0001), shorter times to first detectable CMV VL (p = 0.01), and increased mortality (p = 0.003). Compared to placebo, CMVIG recipients had longer times to peak CMV VL (median days 38 vs. 35; log-rank p = 0.049), lower rates of CMV pneumonitis (0% vs. 17.6%, p = 0.01) and fewer cases of severe CMV disease (3% vs. 17.6%, p = 0.04). Using specimens from studies preceding the antiviral prophylaxis era, among moderate- and low-risk LTR, CMVIG prophylaxis was associated with attenuated CMV disease severity and delayed progression of CMV viremia. These findings suggest that CMVIG may offer both clinical and limited antiviral benefits in this population, particularly in settings where standard antiviral prophylaxis cannot be used.