Detection of varicella zoster virus DNA in human tissue by standard and nested polymerase chain reaction
Results and conclusion
The sensitivity of the PCR assay was determined with cloned VZV DNA. About 200 copies of the target sequence were necessary for detectable amplification by standard PCR and less than 20 copies by nested PCR. Out of 24 human trigeminal ganglia five tested positive for VZV DNA by standard PCR (21%), in eleven cases VZV DNA was detectable using nested PCR (46%). Sequences specific for VZV could be detected in PMBC from children with acute varicella up to six days after the onset of rash by standard (one child) or nested (three children) PCR. This confirms that at the time of haematogenous spread before and during the rash viral DNA can be found within the mononuclear cells. Thus the use of nested primers enhances the sensitivity of the assay and allows the detection of only a few genomic copies of viruses in human tissues.