Standard solution-phase PCR cannot localize the amplified DNA products in cells or tissue sections. Recently, in situ PCR technique which combines PCR with in situ hybridization was developed and applied to detect target DNA or gene expression in the tissue sections.

The purpose of this study was to detect the presence of HSV type-1 DNA in herpes simplex lesions by using hot start PCR in situ hybridization and hot start in situ PCR and to compare the sensitivity and specificity of the two methods. The sensitivity and specificity of multiple overlapping primers and a single primer pair in hot start in situ PCR were also compared.

We performed hot start PCR in situ hybridization and in situ PCR with multiple overlapping primers, and hot start in situ PCR with a single primer pair in paraffin-embedded, formalin-fixed tissues.

HSV type-1 DNA was detected in 4 (80%) of.5 cases of herpes simplex and negative in all cases of herpes zoster, verruca vulgaris, and normal skins. One negative case of herpes simplex could not be detected by HSV type-1 specific primers because it might be caused by HSV type-2. There was no difference in the sensitivity, specificity, and intensity of signals between the three methods.

Hot start in situ PCR with a single primer pair is a simpler, easier, and more rapid technique for detecting the HSV type-1 DNA in lesional tissue sections with similar sensitivity and specificity than hot start PCR in situ hybridization and hot start in situ PCR using multiple overlapping primers.