Tissue distribution of Epstein-Barr virus genotypes in hosts coinfected by HIV

In healthy people, oral and pharyngeal epithelium preferentially carries Epstein-Barr virus (EBV) belonging to a genotype that possesses three copies of a 29 base-pair repeat in the first intron of the BZLF-1 gene, while peripheral blood mostly carries a genotype that bears two copies. Whether EBV shows differential tropism in HIV-1-coinfected hosts, who are prone to develop oral hairy leukoplakia, has not been studied.

Tongue scrapings and CD45+-enriched peripheral blood cells of 20 HIV1-infected patients and 40 healthy controls were examined. EBV-specific DNA was amplified from segments in the first intron of the BZLF-1 gene, in exon C of the LMP-1 gene, and the type A/B-specifying domain of the EBNA-3C gene. Size polymorphisms of these amplicons were assessed by agarose gel electrophoresis, and DNA sequence differences among BZLF-1 gene amplicons by single-strand conformation polymorphism analysis.

The predominant EBV genotype in peripheral blood as well as tongue carried two copies of the BZLF-1 repeat. In controls, although the BZLF-1 genotype with two copies was exclusively detected in the blood, the genotype with three copies predominated in the tongue. The findings could not be correlated with EBV genotyped according size polymorphisms in the EBNA-3C or LMP-1 genes. DNA sequences of a proportion or all of the clones derived from the BZLF-1 amplicons in the tongues of HIV-1-infected patients were identical to those in the blood.

These findings are consistent with EBV haematogenous superinfection of the tongue of HIV-positive individuals. Such superinfection may precede or lead to the development of oral hairy leukoplakia.