Epstein-Barr virus load in the peripheral blood of patients with rheumatoid arthritis: accurate quantification using real-time polymerase chain reaction.

Objective: To determine whether patients with rheumatoid arthritis (RA) have elevated Epstein-Barr virus (EBV) load in their peripheral blood mononuclear cells (PBMCs) and whether it is correlated with the HLA-DR genes they express, we developed an accurate EBV DNA quantitative assay using real-time polymerase chain reaction (PCR) with fluorescent probes.

Methods: We studied the EBV DNA load in the PBMCs of 84 patients with RA, 69 normal controls, and 22 patients with rheumatic conditions other than RA. A 214-bp segment from the long internal repeat of EBV was amplified from 500 ng of PBMC DNA (150,000 cells) and quantified by real-time PCR with fluorescent probes.