Monitoring HCMV Infection With Quantitative Real-Time PCR in HCMV-Positive Orthotopic Liver Transplant Recipients, and Predictive Factors for Treatment of the First Episode of HCMV Viremia

Use of Viral Load as a Surrogate Marker in Clinical Studies of Cytomegalovirus in Solid Organ Transplantation: A Systematic Review and Meta-analysis

Symptomatic cytomegalovirus (CMV) disease has been the standard endpoint for clinical trials in organ transplant recipients. Viral load may be a more relevant endpoint due to low frequency of disease. We performed a meta-analysis and systematic review of the literature. We found several lines of evidence to support the validity of viral load as an appropriate surrogate end-point, including the following: (1) viral loads in CMV disease are significantly greater than in asymptomatic viremia (odds ratio, 9.3 95% confidence interval, 4.6-19.3); (2) kinetics of viral replication are strongly associated with progression to disease; (3) pooled incidence of CMV viremia and disease is significantly lower during prophylaxis compared with the full patient follow-up period (viremia incidence: 3.2% vs 34.3%; P < .001) (disease incidence: 1.1% vs 13.0%; P < .001); (4) treatment of viremia prevented disease; and (5) viral load decline correlated with symptom resolution. Based on the analysis, we conclude that CMV load is an appropriate surrogate endpoint for CMV trials in organ transplant recipients.

Sero-epidemiological survey of human cytomegalovirus-infected children in Weifang (Eastern China) between 2009 and 2012

Background

To understand the prevalence and characteristics of human cytomegalovirus (HCMV) infection in children in the Weifang area, and to provide information for its prevention and treatment.

Methods

A comprehensive survey was performed from 2009 to 2012 in 7582 children from birth to 6 years of age hospitalized in the Maternity and Child Health Hospital of Weifang. ELISA HCMV serology results and survey data were analyzed by age group and socio-economic level. The infection rates were based on IgG and IgM serology.

Results and conclusions

The overall infection rate from IgG and IgM in the Weifang area from 2009 to 2012 was 42.5% (3496/7582), among which 34.2% were HCMV-IgG positive, suggesting past infection. Overall, the probability of active HCMV infection showed no gender difference in any age group (P >0.05). Recent infections centered on the first 6 months of life, presumably due to breastfeeding. Among the 654 children hospitalized for active HCMV infection, 379 (57.9%) were from rural areas and 275 (42.1%) from urban areas, showing that active infection in the countryside was higher than that in the city (χ² = 32.65, p <0.01).

[Comparison between the LightCycler CMV Quant Kit (Roche Diagnostics) with a standardized in-house Taqman assay for cytomegalovirus blood viral load quantification]

The broad use of cytomegalovirus (CMV) viral load quantification in blood to follow immunosuppressed patients need standardized assays. Choice of whole blood allows follow-up for several viruses and simplifies pretreatment and storage of samples.

METHODS

We therefore evaluated the LightCycler CMV Quant Kit (Roche Diagnostics) assay on whole blood after a manual extraction (High Pure viral nucleic acid kit, Roche Diagnostics), using as a reference an in-house Taqman assay (LC1UL83) which has been validated in various clinical situations. A panel obtained by serial dilutions of a virion stock in CMV whole blood, a commercial plasma quality control (VQC, Argène, France) crude or diluted in whole blood, infected cells extracts and 46 clinical samples from transplanted patients were tested simultaneously by both techniques.

RESULTS

For plasma quality controls, both PCR assays are correlated VQC (R(2)=0.93). On whole blood or infected cells dilutions, correlation shows an overestimation by the LC1UL83 assay (mean 1.2 log copies/ml) over 3 log though R(2)=0.94. Results with CMV Quant Kit are closer to expected values. Results on clinical samples are close to quality controls with a lower variation of quantification (0.76 log copies/ml).

CONCLUSION

CMV Quant Kit performs well when compared with a clinically validated PCR. Quality control results showed discrepancies between plasma and whole blood, demonstrating the need for whole blood standardized panels to compare the methods. This underlines the need to follow a patient with the same technique during his follow-up.