Measurement and assessment of cytomegalovirus of immunoglobulin (Ig) g titer in preparations.

Cytomegalovirus (CMV) remains the most important pathogen following solid organ transplantation and is the major cause of recipient morbidity and mortality during the first 6 months posttransplantation. To prevent CMV infection and/or to prevent symptomatic CMV disease, immunoglobulin (Ig) G including hyperimmune CMV IgG are used alone or in combination with antiviral medications. The CMV IgG titer, however, has a wide range and frequently depends on the company supplying the Ig preparation even if the preparations come from the plasma pool of a national blood donation agency. In the present study, we therefore simultaneously measured and evaluated the CMV IgG titers in various Ig preparations using two common methods: the neutralizing antibody (NT) and enzyme immunoassay (EIA). The CMV IgG titer in the present study indicated different values using both methods among Ig preparations that were made from the plasma pool of a national blood donation agency (about 3.5- or about 1.7-fold difference using the NT or EIA methods, respectively). Furthermore, there were no correlations in the CMV IgG titer between our findings and published data from the manufacturers, or between the two methods tested here. These findings suggest the importance and necessity of a standard method and/or sample for the measurement and assessment of CMV IgG in Ig preparations.