Correlation between human cytomegalovirus quantitative p72 antigenemia and viremia

We present a prospective study of the correlation between the human cytomegalovirus (HCMV) quantitative antigenemia with monoclonal antibody to p72 protein (immediate-early antigen) and the number of infected cell foci detected in the shell-vial culture. A comparative study was made of the value of quantitative antigenemia (pp65 and p72) in 14 patients.

The average value of the pp65 antigenemia was 195 pp65-positive PMNLs per 10(5) PMNLs (range 10-1000) and that of the p72, 21 p72-positive PMNLs per 10(5) PMNLs (range 0-120) (P < 0.001). The p72 antigenemia value represented 10.7% of the pp65 value (range 4.4-70%). A statistical correlation was observed between the total number of infected cell foci detected in the shell-vial culture and the total number of p72-positive PMNLs (P < 0.001), but not with the number of pp65-positive PMNLs (P = 0.4). A study of the number of infected cell foci detected in the shell-vial per 100000 PMNLs inoculated showed a statistical correlation with the value of the p72 antigenemia (P < 0.001).

According to results, there seems to be a general population of PMNLs carrying viral particles which are defected by means of the pp65 monoclonal antibody, and a subpopulation carrying active and replicative viral particles which is detected with the p72 antibody. This last subpopulation would be responsible for the formation of infected cell foci in the shell-vial culture. However due to the technical difficulties presented by the routine performance of p72 antigenemia, we recommend the routine application of the quantitative shell-vial culture and the use of the number of infected cell foci x 100000 PMNLs inoculated as a parameter of replicative viral load for the diagnosis of infection and disease caused by HCMV.