Coinfection of multiple strains of Epstein-Barr virus in immunocompetent normal individuals: reassessment of the viral carrier state.

This study reassesses the occurrence of Epstein-Barr virus (EBV) diversity and coinfection versus dominance of a single viral strain within immunocompetent normal carriers. Polymerase chain reaction analysis of several different polymorphic loci of the EBV genome was performed on collections of peripheral blood mononuclear cells and multiple lymphoid and epithelial tissues of the same individuals. Autopsy specimens from 15 individuals who died of causes unrelated to EBV infection served as normal viral carriers. Unexpectedly, coinfection of multiple distinct strains of EBV of the same type (usually type 1) and less frequently of both types 1 and 2 was found to be very high within individual viral carriers. These data indicate that coinfection with multiple EBV strains is much more prevalent in normal carriers than previously appreciated, which in turn has direct implications on EBV persistence, host-viral interaction and pathogenesis.