Although both PBMCs and plasma were useful as material for EBV-specific RQ-PCR in immunosuppressed patients and nonimmunosuppressed individuals, the specificity of analysis seemed to be higher if plasma was taken for analysis.

Measurement of Epstein-Barr virus (EBV) load is useful in peripheral blood for detecting primary and reactivated EBV-infections especially in immunosuppressed patients being at high risk for developing posttransplant lymphoproliferative disorder. For quantification of EBV DNA in peripheral blood of patients two real time polymerase chain reaction (RQ-PCR) assays were developed detecting sequences specific for the BAM HI-W and BAM HI-K region of EBV. In order to determine the optimal material of peripheral blood for RQ PCR analysis, DNA preparations of whole blood, peripheral blood mononuclear cells (PBMC) and B cells from 11 healthy, EBV-seropositive individuals were analysed in parallel and compared with regard to efficiency and sensitivity. While in whole blood preparations inhibitors of RQ PCR were detected influencing sensitivity, analysis of B cells being most sensitive is limited by being too labour intensive. In contrast, analysis of DNA preparations of PBMCs is sensitive enough to frequently detect EBV-specific sequences in all individuals tested and the preparation of PBMCs itself needs only a reasonable time. Thus, longitudinal monitoring of EBV load in peripheral blood of patients is possible by RQ-PCR, the optimal material for analysis being PBMCs.