Detection of Epstein-Barr virus and human herpes virus type 6 in saliva from patients with lymphoproliferative diseases by the polymerase chain reaction.

Direct detection of these viruses was made by using the PCR for amplifying viral DNA. In virtually all adults low levels of the herpesvirus can be detected. Therefore it is necessary to quantitate the amount of viral DNA, and a method to compare the plasmid containing the cloned target gene was used here. After 35 cycles of amplification, 10 copies of the viral DNA per 100 microliters saliva were detected. The PCR was used to detect increased levels of EBV and HHV-6 in saliva from patients with lymphoproliferative diseases, suggesting that these viruses may play a part in their pathogenesis. Viral detection by such highly sensitive methods as PCR may allow better monitoring of medication, as well as early detection of EBV- and HHV-6 related diseases that may arise in these patients. The great sensitivity of PCR and its ability to analyse very small samples make this technique most suitable for clinical diagnosis.