Tracing of the molecular remnants of herpes virus infections in necrotic skin tissue

We have established an assay system to detect herpesvirus-derived transcripts in lesional crusts. Fifteen patients with herpes simplex (HS), 21 with herpes zoster (HZ), 2 with varicella, and 20 with irrelevant diseases were enrolled in the present study. Total RNA was extracted from crusts or scales, and converted to cDNA. Virus-encoded transcripts were amplified using reverse transcriptase (RT)-PCR. Housekeeping gene transcripts such as beta2-microglobulin (β2-MG) and beta-actin (β-actin) mRNA were also examined, and an efficient preservative condition of the crusts was determined. With extracted RNAs, β2-MG and β-actin mRNA were successfully amplified in all crust samples. Herpes simplex virus (HSV)-specific, lytic cycle-related transcript, UL30 mRNA was detected in all 15 HS samples, including 13 samples of HSV-1- and 2 of HSV-2-encoded UL30 mRNA, respectively. Of 23 samples, including 21 HZ and 2 varicella cases, varicella zoster virus (VZV)-specific, lytic cycle-related transcript, ORF40 mRNA was detected in 22 samples. In a control group, no UL30 and ORF40 mRNA were detected. Crust samples that had been stored without any pretreatment or preservative for 6 months at room temperature (RT) were available for the present assay. When compared with the freshly obtained materials, the amount of β2-MG mRNA was reduced to 51% in the stored samples covered with adhesive tape, to 48% in a sample left at R.T. without any treatment, and to 1.2% in the samples stocked in saline for 5 days. Herpes virus- and host-derived transcripts contained in crusts can be detected by RT-PCR amplification. Crusts or dry epidermal necrosis with inflammatory cells may provide beneficial diagnostic information.