PCR analysis of human telomeric repeats present on HHV-6A viral strains.

Human herpesvirus 6 (HHV-6) presents a perfect tandem array of human telomeric repeats (TRS) at both identical direct repeats (DR). Several researchers have reported a different TRS copy number by sequence analysis of HHV-6 DR's cloned fragments so it has been hypothesized that number of TRS is unstable. By PCR we show that the TRS copy number of U1102 HHV-6 variant A strains is stable during viral cultivation in cell lines and each HHV-6 variant A strain, detected in pathologic specimens, is characterized by a specific TRS copy number.