Coinfection with multiple strains of the Epstein-Barr virus in human immunodeficiency virus-associated hairy leukoplakia.

Epstein-Barr virus DNA was analyzed from specimens of hairy leukoplakia, an oral lesion that occurs in patients infected with the human immunodeficiency virus. The simultaneous presence of both type 1 and type 2 Epstein-Barr virus was demonstrated by Southern blot analysis and polymerase chain reaction assay. Restriction fragment length polymorphisms in the BamHI WYH region and in clones of the EcoRI C region suggested the presence of multiple strains of type 1 and type 2 viruses. The demonstration of multiple variably sized BamHI H fragments on Southern blot analysis and cloning of the EBNA-2 gene coding region also suggested the presence of multiple viral strains or variants coinfecting hairy leukoplakia. Recombination of the viral genome in and around the EBNA-2 gene apparently generated viral variants that replicated efficiently, one of which appeared to increase in abundance in a lesion over time. These data indicate that hairy leukoplakia involves coinfection with multiple strains of replicating Epstein-Barr virus and the endogenous generation of viral variants, some of which have mutations of the EBNA-2 gene.